![]() | Yellowstone GuideSpring 2021 |
The Spring 2021 edition of the Yellowstone Visitor Guide for Yellowstone National Park (NP) in Idaho, Montana and Wyoming. Published by the National Park Service (NPS).
covered parks
Yellowstone Visitor Guide
Spring 2021
National Park Service
U.S. Department of the Interior
1st Edition
Welcome to Yellowstone National Park
YE L L O W S T O N E I S A P L A C E L I K E N O O T H E R .
Preserved within its boundaries are Old Faithful and
the majority of the world's geysers and hot springs.
An outstanding mountain wildland with clean water
and air, Yellowstone is home of the grizzly bear and
wolf and free-ranging herds of bison and elk. Centuries-old sites and historic buildings that refect the
unique heritage of America's frst national park are
also protected.
Use this visitor guide, combined with the ofcial
brochure map and free park app (see page 2), to
plan a Yellowstone adventure that is:
• SAFE. Yellowstone is very diferent from your
home and can be life-threateningly dangerous.
Your safety is your responsibility. Read the
safety information throughout this guide
and take it seriously.
• SUCCESSFUL. There is so much to do and see
in Yellowstone. Explore things to do on pages
4–7, learn about thermal features and wildlife on pages 8–9, fnd details for developed
areas of the park on pages 10–14, and double-check road openings/closures and construction on the back page.
• RESPECTFUL. The experiences you have in
Yellowstone were made possible by the care
of those who came before you. Extend this
same courtesy to those who will come after
you. Follow all park rules, which are designed
to protect both you and the park.
The park is assisted in fulflling its mission by its
ofcial nonproft partner, Yellowstone Forever.
Proceeds from Yellowstone Forever educational
bookstores, Institute, and philanthropic eforts
support priority park projects and visitor
education. Find more information at
Yellowstone.org or call (406) 848-2400.
Bison graze near Roosevelt Arch at the park's North Entrance.
Travel Alerts
SEASONAL ROAD OPENING
All park roads except the road from the
North to Northeast entrances are closed to
automobiles through April 15.
Weather permitting, park roads will begin
opening in stages starting April 16.
TOWER TO C ANYON ROAD CLOSED
The road between Tower-Roosevelt and
Canyon Village is CLOSED all year.
MOUNT WASHBURN TR AILS CLOSED
All trails to the top of Mount Washburn
will be closed.
See back page for details
COVID-19 Safety Alert
The National Park Service follows CDC guidance to reduce the spread of
COVID-19. Check locally, on the park website, and in the park app for updates
and changes in park operations. Thank you for helping to keep yourself and
others safe and healthy.
6 feet
2 meters
Mammoth
Hot Springs
Tower-Roosevelt
CLOSED
Norris
Canyon Village
Keep Wildlife Wild
Yellowstone is an incredible
place to view wildlife. All the
large mammals present when
Yellowstone became a park in
1872 are here today: grizzly and
Wearing a mask is required in all common areas in buildings owned, black bears, wolves, mountain
rented, or leased by the National Park Service, including, but not
lions, elk, bison, pronghorn,
limited to, park visitor centers, administrative ofces, lodges, gift shops, moose, and bighorn sheep.
and restaurants. Masks are required outdoors where physical distancing cannot reasonably be maintained. Masks are not required for • Wildlife are dangerous.
those under the age of two or when actively eating or drinking.
• Do not approach, encircle,
follow, or feed any animal.
Practice social distancing. Maintain at least 6 feet (1.8 m) of distance
• Bison, bears, and elk injure and kill people.
between you and others.
• Stay at least 100 yards (91 m) from bears and wolves.
• Stay at least 25 yards (23 m) from all other animals, including bison and elk.
Wash your hands with soap and water for at least 20 seconds,
• If an animal moves closer to you, move away
or use hand sanitizer.
to maintain the appropriate distance.
• Do not stop on or block a road.
Cover your mouth and nose when you cough or sneeze.
• Use pullouts; stay in your car to watch animals.
• Store food and trash securely. Backpacks are not secure.
If you feel sick, do not visit the park.
• Do not feed any animals, even birds and squirrels.
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Yellowstone National Park
National Park Service
U.S. Department of the Interior
Emergency
Information
TTY
Park Entrance Radio
Dial 911
307-344-7381
307-344-2386
1610 AM
Park Tip Line
307-344-2132
To report a crime or criminal activity.
Leave as much detail as you can. Remain
anonymous, or leave a name and number.
Facilities and Services
Medical Services
Accessibility
Yellowstone emergency response
A printed guide with accessibility information
Cell phone service is very limited in the park
and ambulance service
is available at visitor centers and on the park
and surrounding areas. General cell coverage
Call 911
website (go.nps.gov/YELLaccess).
areas are shown on the map on the back page
Text 911 is not available in Yellowstone.
of this guide.
Qualifed service animals are welcome
Medcor provides medical care, from
throughout the park and in all park facilities.
Emergency 911 service by cell phone is only
emergencies to minor needs, at:
However, they must be leashed and under your
available in coverage areas. Text 911 is not
• Mammoth Clinic
control at all times.
available in Yellowstone.
Year-round
During peak hours and periods of heavy visita-
307-344-7965
tion, the cellular network may be very slow.
• Lake Clinic
NPS Yellowstone National Park App
Plan and enrich your visit
with the offcial, free NPS
~ Cell Service
5/28–9/19 8:30a–8:30p daily
Your provider may or may not roam on networks
307-242-7241
in Yellowstone.
• Old Faithful Clinic
Yellowstone National Park
5/14–10/1 7a–7p daily
As a courtesy to others, silence your mobile
App. Digitally explore the
307-545-7325
device while enjoying Yellowstone.
world's frst national park—by map or by
topic of interest. Discover the natural and
Eastern Idaho Regional
cultural stories in context with their loca-
Medical Center
tions. Find the information you need about
and other area hospitals
visitor centers, events, lodging, places to
provide air evacuation
eat and shop, and services throughout the
Available for free:
and trauma care.
• Albright Visitor Center
Wi-Fi
park. Download the app and app con-
in Mammoth Hot Springs
tent before you begin your adventure,
as cell service and Wi-Fi are limited in
Data speeds are very limited outside of
Yellowstone.
Mammoth Hot Springs.
Follow @YellowstoneNPS
Grizzly bear (Ursus arctos horribilis) near Obsidian Creek in late April.
Lodging, Dining, and Tours
As one of Yellowstone's offcial concession
companies, Yellowstone National Park Lodges
offers lodging, dining, camping, and a
variety of tours and activities.
Visit YellowstoneNationalParkLodges.com
for the most up-to-date information,
which may change due to COVID-19.
For reservations and information,
ask at park hotels, or contact
Yellowstone National Park Lodges:
Phone
307-344-7311, 866-439-7375
TDD
307-344-5395
Online
YellowstoneNationalParkLodges.com
Email
Reserve-YNP@Xanterra.com
Mail
PO Box 165
Yellowstone, WY 82190
Mammoth Hot Springs Hotel
2 Yellowstone Visitor Guide
Safety and Regulations
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Watch Wildlife Safely
Store Food Securely
Yellowstone ofers wildlife watching opportunities
that are unparalleled in the lower 48 states. All the
large mammals present when Yellowstone became a
park are here today: grizzly and black bears, wolves,
mountain lions, elk, bison, pronghorn, moose, and
bighorn sheep. You might also see a variety of birds,
including bald eagles.
Do not feed any wildlife, including small mammals
and birds. Eating human food is unhealthy and encourages aggressive behavior.
Protect Yourself and the Animals. Obey Park Rules.
• Stay at least 100 yards (91 m) from bears and
wolves and at least 25 yards (23 m) from all other
animals, including bison and elk.
• If an animal moves closer to you, move away
to maintain the appropriate distance.
• Do not surround, crowd, or disrupt any animal's
path of movement.
Looking for Wildlife?
• If other visitors put you or wildlife in danger, leave
• To conserve energy, most wildlife are active in the
the area and notify a park ranger.
cool of dawn or dusk.
• Spotlighting—viewing animals with artifcial light—
• Animals are everywhere in the park, but it is easier to
is illegal.
see them in open meadows and sagebrush than in • Calling to attract wildlife is illegal. You may not bugle
dense forest.
to elk, howl at wolves, or make bird calls of any kind.
• Find a place with a broad view for your binoculars or • Tracking wildlife with electronic equipment is not
spotting scope, and be prepared to wait.
permitted.
All food, trash, and scented items must be kept inaccessible to bears at all times. Tents, truck beds, and
picnic tables are not secure. In some areas, ravens
have learned to unzip packs and scatter the contents.
None of these items, even if clean and empty, may
be left unattended at any time:
• Water and beverage
containers
• Food, including condiments,
even if in containers
• Cooking or eating utensils
• Cosmetics and toiletries
• Stoves and grills
• Pet food and bowls
• Coolers and ice chests
• Pails, buckets, wash basins
• Garbage, bagged or not
Enjoy watching Yellowstone’s animals but STAY SAFE. They are WILD and DANGEROUS.
Other people
2 yards (2 m)
Bison, elk, and all other wildlife
Bears and wolves
25 yards (23 m)
Drones
Firearms
100 yards (91 m)
Pets
Launching, landing, or operating unmanned
Firearms are allowed in national parks pursuant to state
Pets are not allowed on trails or boardwalks, in the back-
aircraft (drones) on lands and waters administered by the
and federal regulations. They are prohibited in facilities where
country, or in hydrothermal basins. Where allowed, pets must
National Park Service is prohibited.
signs are posted, such as visitor centers, government offces, and
be leashed and remain within 100 feet (30.5 m) of a road or
some concession operations. Discharge of frearms is prohibited.
parking area.
n Lost and Found
?
Possession and use of weapons, such as air guns, bows and arrows, spears, and slingshots, is also prohibited. Details are avail-
Do not leave a pet unattended, tied to an object, or without
able at go.nps.gov/yell-laws.
adequate food, water, shade, ventilation, or other basic needs.
Call 307-344-5387 to report or retrieve items lost in lodging
Owners must bag and dispose of pet waste. We recommend that
facilities. In other parts of the park, call 307-344-2109 or look
someone in your group remain with your pet at all times to per-
online: go.nps.gov/lost-and-found.
sonally ensure their well being.
Spring 2021 3
Things to Do
Camping
Yellowstone offers 12 campgrounds
with over 2,000 sites.
In early spring, Mammoth Campground
is the only campground open in the
park and is frst-come, frst-served.
During the park's busy season, from
the beginning of May through the fall,
many campsites can be reserved ahead
of time. Due to high demand, reservations are highly recommended.
First-come, frst-served sites are available during the busy season at Indian
Creek, Lewis Lake, and Pebble Creek
campgrounds.
A campsite at Pebble Creek Campground.
No Overfow Camping
There are no overfow camping areas
available in Yellowstone. No camping
or overnight vehicle parking is allowed
in pullouts, parking areas, picnic
grounds, or any place other than a
designated campground. Additional
camping may be available in neighboring communities.
Check-In and Check-Out
Registration desks at Yellowstone
National Park Lodges campgrounds
are open 7 am to 10 pm during peak
season, and 8 am to 9 pm during early
and late season. Check-out at reservable campgrounds is 11 am.
Length of Stay
Camping is limited to 14 days from
July 1 through Labor Day (frst Monday in September) and to 30 days the
rest of the year.
Discounts
Holders of Senior and Access passes
receive a 50 percent discount on camping fees except at Fishing Bridge RV
Park.
Quiet Hours
From 10 pm to 6 am, no loud audio
devices or other noise disturbances are
allowed.
Group Camping
Group camping (tents only) is available
at Bridge Bay, Grant, and Madison
for organized groups with a designated leader. Fees range from $136 to
$399 plus tax and utility fee per night,
depending on group size. Advance reservations are required at 307-344-5437
or ynpsa@xanterra.com.
Food Storage Boxes (see right)
Available at each campsite at Indian
Creek, Lewis Lake, Mammoth, Norris,
Pebble Creek, and Slough Creek campgrounds. Many campsites in other
campgrounds are also equipped with
bear-proof storage boxes.
Food storage box
Campgrounds
In Order of Opening
Reservation Status
Dates
Rate
Sites
Elevation (ft/m)
Features
RV sites
Mammoth
Winter operations
First-come, frst-served
Jan 1 – Apr 30
Oct 16 – Dec 31
$25
38
6,200 ft (1,890 m)
A, F, G
Most are pull-through
Mammoth
Summer operations
All sites reservable
recreation.gov
May 1 – Oct 15
$25
85
6,200 ft (1,890 m)
A, F, G
Most are pull-through
Madison
All sites reservable
307-344-7311
May 14 – Oct 17
$27 *
278
5,800 ft (2,070 m)
A, F, DS, G
Call for availability
Canyon
All sites reservable
307-344-7311
May 21 – Sep 19
$32 *
273
7,900 ft (2,410 m)
A, F, L, 2S, DS, G
Call for availability
Bridge Bay
All sites reservable
307-344-7311
Jun 11 – Sep 6
$27 *
432
7,800 ft (2,285 m)
A, F, DS, G
Call for availability
Indian Creek
First-come, frst-served
Jun 11 – Sep 13
$20
70
7,300 ft (2,225 m)
A, V
10 sites are 35 ft
35 sites are 30 ft
Pebble Creek
Some sites reservable
recreation.gov
Jun 15 – Sep 27
$20
27
6,900 ft (2,100 m)
A, V
Some long pull-throughs
Slough Creek
All sites reservable
recreation.gov
Jun 15 – Oct 12
$20
15
5,260 ft (1,905 m)
A, V
14 sites are 30 ft
walk frst to assess sites
Lewis Lake
First-come, frst-served
Jun 15 – Nov 7
$20
85
7,800 ft (2,285 m)
A, V
All sites are 25 ft or less
Grant Village
All sites reservable
307-344-7311
Jun 18 – Sep 12
$32 *
430
7,800 ft (2,285 m)
A, F, L, 2S, DS, G
Call for availability
Norris
CLOSED
Fishing Bridge RV Park
CLOSED
Tower Fall
CLOSED
4 Yellowstone Visitor Guide
Campground Features
*
A
F
V
L
2S
DS
G
Rate does not include tax or utility
pass-through
Accessible sites available
Flush toilets
Vault toilets
Pay laundry onsite
Two showers included each night
Dump station
Generators allowed 8 am to 8 pm
Campfres
are allowed only in designated grills or rings in park campgrounds, some picnic areas, and
specific backcountry campsites.
Fully extinguish all campfires—they
should be cool to the touch—before
leaving them.
Things to Do
Safely storing items at a backcountry site.
Backcountry Camping
Overnight backcountry camping is only allowed in
designated sites and requires a permit. Detailed
information on backcountry permits, fees, and
advanced reservations is available online:
go.nps.gov/YELLbackcountry.
Boating on
Yellowstone Lake.
Cutthroat trout
Fishing
Boating
Permits are free prior to Memorial Day.
General fshing season opens May 29 and closes
November 7, 2021. Some areas remain closed until
June 15. Fishing permits are required in Yellowstone; state-issued fshing permits are not valid
within the park. Anglers 16 years or older need a
permit; younger children can fsh for free with a permitted adult.
The boating season opens May 29 and closes
November 7, 2021. All watercraft (motorized
boats, non-motorized boats, and foat tubes) must
have a permit and be inspected for aquatic invasive species by park staff. Any watercraft suspected
of harboring AIS will be subject to a non-chemical
decontamination treatment.
From Memorial Day through September 10,
a per-person, per-night fee applies:
• Backpackers and boaters: $3 per person per night
Group maximum $15 per night
• Groups with stock animals: $5 per person per night
Fishing regulations in Yellowstone protect the
unique values of the park ecosystem and conserve
native fsh species. Copies of the complete park regulations are available wherever permits are sold and
online at go.nps.gov/fsh.
Aquatic Invasive Species are nonnative plants and
animals that can cause irreversible harm to the ecosystem. New Zealand mudsnails, whirling disease,
and lake trout have already resulted in loss of native
fsh or closure of some park areas.
For current trail conditions visit:
go.nps.gov/YELLbackcountryreport.
Possession limits and closures vary throughout the
park. Anglers are responsible for knowing the regulations in the area they are fshing. Anglers are also
responsible for knowing how to tell the diference
between species. Native fsh must be released
unharmed back into the water immediately.
These include:
• Arctic grayling
• Cutthroat trout
• Mountain whitefsh
Watercraft users and anglers are asked to inspect
all items that may come in contact with park waters,
ensuring that they are clean, drained, and dry.
Riding the Yellowstone River Trail.
Horses, Mules, and
Other Stock Animals
These tackle and gear restrictions apply:
• Hooks must be barbless.
• Tackle and lures must be non-toxic. Lead tackle
is not allowed.
• Bait is prohibited.
• Felt-soled footwear is not permitted.
Traveling in the Yellowstone backcountry with horses, mules, or llamas is an exciting way to see the park.
By their very nature, these large animals have the
potential to leave great impacts on the land.
Permits are required for both day rides and overnight trips. To get a permit and plan a safe, enjoyable,
low-impact trip, contact a backcountry ofce or look
online at go.nps.gov/YELLhorseride.
• Trails typically open for stock use July 1. Some
trails may open earlier or later depending on trail
conditions.
• Proof of a negative Coggins test is required.
• Hay is prohibited in the backcountry, and weedfree hay restrictions are enforced in other areas.
• Stock may not be left at trailheads or kept in
front-country, drive-in campgrounds overnight.
Motorized boating is allowed on Lewis Lake and
most of Yellowstone Lake. Only non-motorized boating is allowed on most other lakes. Only one river
is open to non-motorized boating: the Lewis River
channel between Lewis and Shoshone lakes.
If you plan to boat in the park, familiarize yourself
with Yellowstone National Park boating regulations
and information about inspections and permits,
available online at go.nps.gov/YELLboating.
BOAT PERMIT AND AIS INSPECTION LOCATIONS
Motorized and non-motorized watercraft
(including angler foat tubes):
• Bridge Bay Ranger Station
• Grant Village Backcountry Ofce
• Lewis Lake Ranger Station
Angler foat tubes only:
• Locations listed above
• Northeast Entrance Station
• Bechler Ranger Station
Gardner River
below Osprey Falls
Swimming
For more information, visit go.nps.gov/YELLboating
or call 406-581-9040 (Grant AIS inspector) or
406-823-9006 (Lake AIS inspector).
Park waters are swift and cold.
• Swimming in hot springs or their runoff
is prohibited.
• Swimming in park rivers is not recommended.
Currents can be dangerously strong and fast.
• Swimming in Yellowstone lake is not recommended.
Average lake temperature is approximately 41°F (5°C).
Certain Boats Banned
Boats with sealed internal water ballast
tanks are temporarily banned in the park
to minimize the risk of introducing aquatic
invasive species.
Spring 2021 5
Things to Do
Day Hiking
More than 1,000 miles of hiking trails
wind through Yellowstone National
Park. Whether you hike for half a mile
or more than 10, the backcountry can
be an escape from the crowds and a
chance to get in touch with the wilderness that Yellowstone preserves.
Find hikes using the free park app (see
page 2) or at go.nps.gov/YELLdayhikes.
go.nps.gov/YELLbackcountryreport
has information on seasonal closures
and trail conditions. Be prepared for
wildlife encounters, hike in groups of
three or more, and carry bear spray on
all hikes.
Hiking in Bear Country
Hiking in bear habitat has inherent
risks. You are likely to be safer if you
stay on roads and ofcial trails, but your
safety cannot be guaranteed. Federal
regulations require you to stay at least
100 yards (91 m) away from bears.
Learn more: go.nps.gov/bearspray.
Bear spray is available for
purchase in Yellowstone
where stores are open.
Bear spray cannot be taken
on airplanes or thrown in
the trash. Canisters can be
recycled in the park. Check
locally or online for locations.
• BE ALERT FOR BEARS.
• MAKE NOISE
in areas with limited visibility.
• CARRY BEAR SPRAY,
one can with each adult,
and know how to use it.
• HIKE IN GROUPS
of three or more people.
• DO NOT RUN;
back away slowly.
Hiking the Beaver Ponds Trail.
Photographers in Lamar Valley
Photography
Yellowstone is one of the best places
in the world to photograph wildlife.
The Name of the Game is Patience
To get the best shot, you will spend
more time waiting and observing than
taking photos. Look for patterns in
animal behavior that can help you get
a great shot. You may have to wait a
while, so be ready.
Know Your Camera's Limits
A cell phone camera will not be able to
capture the same resolution and detail
as a more advanced standalone camera
with large lenses. Good photography
isn't about getting close to the animal
for a close-up. It's about having the
right equipment for the job.
6 Yellowstone Visitor Guide
Biking in the spring.
Bicycling
Stay Safe Behind and in Front of the
Camera
An unusual vantage point can add drama to your image, but you don't want
to add the drama of a hospital visit to
your trip. Never sacrifce safety for a
photograph.
• Be Aware of Your Surroundings
Stay behind fences and guard rails.
Never turn your back on wild animals.
• Keep Children Close to You at
All Times
Never try to pose them with wildlife.
• Stay Out of the Road
Do not stop your vehicle in the road
or stand in the roadway. Do not block
any portion of the road with tripods,
chairs, or other objects. Do not block
the free fow of trafc.
Bicycling, including the use of e-bikes,
is permitted on established public
roads, parking areas, and designated
routes. Bicycles are subject to the same
trafc rules as automobiles and are prohibited on trails and boardwalks.
Park roads are narrow and winding
with few shoulders, so regulations
require cyclists to ride single fle, and
we strongly recommend wearing a
helmet and high-visibility clothing.
Smoking Is
Prohibited
in geyser basins, on trails and boardwalks, in buildings, or within 25 feet
(7.6 m) of building entrances.
Road elevations range from 5,300 to
8,860 ft (1,615 to 2,700 m), and services
and facilities are far apart—typically 20
to 30 miles (37 to 56 km). During April,
May, and June, high snowbanks may
make travel more dangerous.
Find information on the park website
at go.nps.gov/YELLbicycling.
•
Take Only Pictures
Removing or possessing natural
or cultural resources (like wildfowers,
antlers, rocks, and arrowheads) is strictly prohibited.
Things to Do
Become a Junior Ranger
Explore Park Heritage
If you're age 4 or older, you can become a Yellowstone Junior Ranger! This program is a way to introduce children—and those young at heart—to the
natural wonders of the park as well as their own role
in preserving these wonders for the future.
Opportunities to connect to the past are
everywhere in Yellowstone. Visit Mammoth Hot
Springs to walk the self-guiding trail around Fort
Yellowstone, which chronicles the US Army's role in
protecting the park. Other historic sites include the
Norris Museum, Obsidian Clif, and the Old Faithful
Inn and Historic District.
The Heritage and Research Center (above) is located
just beyond the North Entrance in Gardiner, Montana. This facility is home to Yellowstone's museum
collection, archives, research library, archeology lab,
and herbarium. Open by appointment only.
Authorized Guides
Many authorized guides and outftters are ready
to show you the wonders of Yellowstone, and each
has a unique approach. Make sure that your guide,
tour company, or other commercial service is fully
authorized by the park. Authorized providers are
listed on the park website at go.nps.gov/YELLtours.
Support Your Park
YE. L LOWS,TO INI E
FOREVER
1
Yellowstone Forever is the offcial nonproft partner of Yellowstone National Park. Their mission
of engagement and support through philanthropy
and education for the park will ensure Yellowstone
remains for generations to come. Programs about
wildlife, plants, geology, and history are perfect for
curious adults and families who want to spend a day
or more exploring the park with a knowledgeable
guide. To learn more, visit Yellowstone.org.
Special use permits are
required for certain activities
including organized gatherings like weddings or
church services, public assemblies and demonstrations,
some commercial activities like commercial travel, and
some types of flming and photography. For more
information, call 307-344-2722.
Report unauthorized operators to a park ranger, or
contact Concessions Management at 307–344–2271.
Covered wagons
at Yanceys Hole.
Make the Most of Your Visit
Yellowstone encompasses more than 2.2 million
Only one day here?
Two or more days?
acres, most of it beyond the reach of roads. One could • Drive to the Old Faithful area and walk around the
• Explore one theme, such as geology, in depth. For
dedicate their entire life to experiencing the park and
Upper Geyser Basin.
example, visit Mammoth Hot Springs to see traverstill never see it all. Here are suggestions for mak• Visit Old Faithful and one other hydrothermal area,
tine formations and view the sedimentary layers of
ing the most of the time you do have.
like Norris, West Thumb, or Fountain Paint Pots. FolMount Everts, then drive through terrain shaped by
low boardwalks and maintained trails to witness hot
glaciers to the Tower-Roosevelt area.
Tour early in the day to avoid crowds.
springs, mudpots, fumaroles, and geysers.
• Visit Yellowstone Lake, the largest high-elevation lake
Most people tour the park from 10 am to 6 pm. Wild- • Begin in Hayden or Lamar valleys to look for some of
in the lower 48 states. Take in the spectacular views
life are most active at sunrise and sunset; arriving
the park's large animals. Bring binoculars or a spotof West Thumb and the Absaroka Mountains from its
before 8 am improves your chances of observing aniting scope, and enjoy animals from a safe distance.
shores. Explore the hot springs, mud pots, and geymals during their active periods. Park entrance gates • For a break from the road, consider one or two modsers of West Thumb Geyser Basin. Hike one of the
are open 24 hours a day.
erate day hikes. Always carry rain gear, extra food
local trails, such as the Scenic Lake Overlook near
and water, bear spray, and other emergency equipWest Thumb.
Visit a hidden gem.
ment when venturing into the backcountry.
• Slow down and try your hand at capturing the beauty
Take a day hike, or stroll one of our historic walking
• Have a picnic. Unpack your basket at any of the 51
of Yellowstone through journaling, painting, or simtours at Fort Yellowstone or Old Faithful. Explore
picnic areas throughout the park.
ply observing.
nearby national park units, national forests, state
forests, and state parks. The region ofers a variety of
public lands for recreation and enjoyment.
Spring 2021 7
Famously Hot Features
Yellowstone was established in 1872 as the
world's frst national park primarily because of
its unparalleled collection of geysers, hot springs,
mudpots, and steam vents.
Stay on Boardwalks
and designated trails. Do not touch any thermal
features, and keep foreign objects out of springs.
It can be windy, so cinch your hats, and secure your
items.
Fumaroles, or steam vents, are the hottest hydrothermal features in the park. They are easier to see in cool
weather.
Geysers erupt with steaming hot water. Variations
in each geyser's underground reservoir determine
whether it is regular and predictable—like Daisy
Geyser in the Upper Geyser Basin—or irregular like
Steamboat Geyser in Norris Geyser Basin.
Hot springs are the most common hydrothermal
features in the park. They vary from frothing mochalike boiling water to clear and calm pools of tremendous depth.
Mudpots are acidic features with a limited water
supply. Their consistency and activity vary with the
seasons and precipitation.
Travertine terraces are found at Mammoth Hot
Springs, where the interactions of water and limestone create chalk-white travertine.
Norris Geyser Basin
How Faithful is Old Faithful? How do geysers work?
Some Like It Hot
Since its frst documentation in 1870, Old Faithful
has been one of the more predictable geysers.
Over time, the average interval between Old Faithful's eruptions has increased or decreased due to
changes in its plumbing from ongoing processes and
earthquakes. The Hebgen Lake Earthquake (1959)
caused an increase in the time between eruptions.
Descendants of the frst life forms to evolve on
Earth live in the extremely hot, sometimes acidic,
habitats in and around hydrothermal features. The
heat-loving microorganisms, called thermophiles,
survive and thrive in Yellowstone's active volcanic
environment.
The average interval between eruptions at Old Faithful Geyser is 94 minutes ± 10 minutes, with intervals
ranging from 54 to 114 minutes.
Geysers are hot springs with narrow spaces in
their plumbing, usually near the surface. These
constrictions prevent water from circulating freely
to the surface where heat would escape. The deepest
circulating water can be more than twice as hot as the
surface boiling point of 199°F (93°C). The surrounding pressure also increases with depth, similar to the
ocean. Increased pressure exerted by the enormous
weight of the overlying rock and water prevents the
water from boiling as it heats up.
As the water rises, steam forms. Bubbling upward,
steam expands as it nears the top of the water column until the bubbles are too large and numerous
to pass freely through the constrictions. At a critical
point, the confned bubbles actually lift the water
above, causing the geyser to splash or overfow. This
decreases pressure on the system, and violent boiling
results. Tremendous amounts of steam force water
out of the vent, and the eruption begins.
8 Yellowstone Visitor Guide
Nourished by energy and chemical building blocks
available in the hot springs, the microbes build vividly-colored communities like those you see in the photo above. The colors vary depending on the types of
microbes, the pH (acidity or alkalinity), temperature
of the feature, and exposure to sunlight.
Millions of individual microbes can connect into
long strands called flaments. Some flaments tangle,
forming mats. Flowing water brings other microbes,
organic matter, and minerals that add to the mat.
Mats can be thin as tissue paper or thick as lasagna.
Because of their fragility, they must not be touched.
Water is expelled faster than it can enter the geyser's
plumbing system, and the heat and pressure gradually decrease. The eruption stops when the water reservoir is exhausted or when the system cools.
Dozens of types of microbes from all three domains
of life can exist in these mats, from Archea in the
hottest, most acidic features to the more widespread
Bacteria and Eukarya.
Yellowstone's geyser basins contain fountain- and
cone-type geysers. Fountain-type geysers shoot
water in various directions from a pool of water.
Cone-type geysers like Old Faithful erupt in a concentrated jet of water from inside a rock formation.
Scientists continue to study the many mysteries of
thermophiles and their extreme habitats in the living
laboratories of Yellowstone's thermal areas and features.
Wild Lands and Wildlife
Wolves in Yellowstone