YELLOWSTONE NATIONAL PARK IS OUR FIRST AND ONE OF THE MOST VISITED NATIONAL PARKS.

IN WINTER ACCESS IS LIMITED AND VISITORS AND WILDLIFE ARE CHALLENGED BY DEEP SNOW AND FIERCE COLD.

THIS PLACE IS WORK, ISN'T IT?

I'VE HAD WORSE WORK.

THE FROZEN LANDSCAPE IS UTTERLY TRANSFORMED FROM SUMMERTIME AND ITS EXPLOSIVE POTENTIAL IS EVEN MORE EVIDENT.

FUNDING FOR IN THE AMERICAS WITH DAVID YETMAN WAS PROVIDED BY AGNES HAURY.

♪ MUSIC ♪ IF YOU ASK PEOPLE AROUND THE WORLD WHAT COMES TO MIND WHEN THEY HEAR THE WORDS NATIONAL PARK, THE MOST COMMON ANSWER WILL BE YELLOWSTONE.

IT'S OUR FIRST NATIONAL PARK FOUNDED IN 1872, THE FIRST NATIONAL PARK IN THE WORLD.

IT'S STILL THE FLAGSHIP OF OUR NATIONAL PARK SYSTEM WHICH IS THE ENVY OF EVERY OTHER COUNTRY.

MILLIONS OF VISITORS COME TO YELLOWSTONE EACH YEAR, THREE MILLION.

ALMOST ALL OF THEM COME IN SUMMERTIME, IN WINTER IT'S A VERY DIFFERENT PLACE.

WE'RE LOOKING HERE AT THE NORTHERN EDGE OF THE YELLOWSTONE CALDERA.

IT LOOKS JUST LIKE A RIDGE BUT IF YOU GET ON THE OTHER SIDE YOU REALIZE IT'S A VALLEY, A VAST VALLEY CAUSED BY THE BLOW OUT OF A MASSIVE AMOUNT OF MAGMA.

INSIDE THE YELLOWSTONE CALDERA, NATURE HAS CREATED CONDITIONS THAT EXIST ALMOST NOWHERE ELSE ON THE PLANT.

IT'S NOT ONLY A CAULDRON OF SEETHING HYDROTHERMAL ACTIVITY BUT IT HAS BECOME AN IDEAL HABITAT FOR SOME OF THE WORLD'S LARGEST MAMMALS, IN GREAT NUMBERS, PROTECTED BY THE EDGES OF THE CALDERA AND FED BY SOME OF THE RICHEST SOILS ANYWHERE IN THE UNITED STATES.

GREAT SIGHTINGS OF BISON.

THAT'S REALLY FRESH SNOW.

IT'S COLD.

IF I CAN SEE MY BREATHE, I SHOULD BE ABLE TO SEE THEIRS.

SO THIS HERD STAYS PRETTY MUCH IN THIS GENERAL AREA.

THERE'S GOOD GRASS.

THE BULLS WILL WEIGH 2,000 POUNDS.

THE FEMALES WEIGH ABOUT 1,500 POUNDS.

BUT THEY HAVE MASSIVE VERTEBRAE WHICH HAVE TO BE PRETTY STRONG TO HOLD A 50 POUND HEAD AND THEY USE THAT HEAD LIKE A BROOM MOVING IT SIDE BY SIDE TO SWEEP ASIDE THE SNOW THEN THEY CAN GET THEIR HEAD DOWN IN.

THERE'S ONE DOING IT NOW.

THEY CAN THEN GET ACCESS TO THE GRASS.

IF THE SNOW GETS TOO DEEP OR IF THERE'S ICE WITH SNOW ON TOP OF IT, THAT MEANS LIFE'S GOING TO BE DIFFICULT.

OVER THE WINTER THEY'LL LOSE 30 PERCENT OF THEIR WEIGHT WHICH FOR A 2,000 POUND BULL MEANS ALMOST 700 POUNDS.

THEY'RE MOVING OFF TO THE RIGHT.

THE SNOW HERE IS A LITTLE DEEPER THAN IT WAS BACK IN WEST YELLOWSTONE.

THERE WE GO.

OKAY, ON FOR OTHER MAMMALS.

THE PRINCIPLE REASON WHY TOURISTS COME HERE, PARTICULARLY IN THE WINTERTIME, IS TO SEE THESE CHARISMATIC, HUGE HERBIVORES, THE ELK, THE BISON.

THE MOOSE ARE NOT AS COMMON IN HERE BUT THEY'RE BIG TOO.

ISN'T IT AMAZING THAT AS COLD AND ALMOST BLEAK AS IT IS UP HERE IT CAN SUPPORT THESE ENORMOUS BEASTS.

THEY'RE VERY GOOD AT WHAT THEY DO.

WE'VE GOT A NEAT COMBINATION HERE OF A NARROW VALLEY, STORMS MOVING THROUGH AND HEATING BY THE SUN AND IT'S PRODUCING THIS FUNNEL EFFECT AND WE'RE GETTING WINDS OF, IT'S GOT TO BE AT LEAST 70 MILES AN HOUR AND I'LL BET IT'S EVEN MORE.

IT'S LIKE A BLIZZARD IS ROCKING THIS VEHICLE LIKE CRAZY.

IT'S GOT TO BE AS CLOSE TO A SNOW TORNADO AS I'VE EVER SEEN.

I MIGHT EVEN CALL IT A SNOW DUST DEVIL.

I'M FROM THE DESERT.

WE HAVE DUST DEVILS BUT THIS IS A SNOW DEVIL.

SNOW IS A HUGE PART OF YELLOWSTONE WINTER.

IT'S NOT TERRIBLY DEEP THIS YEAR.

LOOKS LIKE THE DRIFTS HERE ARE A COUPLE FEET DEEP BUT ON ANY GIVEN YEAR YOU MAY GET 100 INCHES OF SNOW, 200 INCHES OF SNOW IN PARTS OF YELLOWSTONE.

I'M GLAD I ONLY HAVE TO WALK THROUGH TWO AND A HALF FEET HERE BECAUSE IF I HAD TO WALK THROUGH A 20 FOOT DRIFT AND IF I WERE A BUFFALO OR A BISON I WOULD HAVE A VERY HARD TIME SURVIVING.

GEYSERS HAVE THEIR OWN PERIODS, THEIR OWN TIMES OF PENETRATING THE ATMOSPHERE.

THIS ONE IS CALLED CLEPSYDRA NAMED AFTER A GREEK WATER CLOCK.

IT'S PRETTY REGULAR.

YOU CAN COUNT ON IT AND YOU'LL KNOW ANY TIME YOU COME HERE THERE'S GOING TO BE ACTIVITY.

I'M WALKING THROUGH THE EXCRESCENTS, THE SULFUROUS FUMES OF THE RED SPOUTER.

IT'S ACTUALLY RED MUDDY WATER THAT'S GIVING OFF ALL KINDS OF GASES THAT WOULD PROBABLY KILL ME IF I WERE TO STAY HERE MORE THAN 24 HOURS.

THIS WHOLE AREA IS A FUMERAL WHICH IS A PLACE WHERE STEAM ESCAPES FROM VOLCANIC ACTIVITY.

IT'S ONE OF THE SEVERAL DIFFERENT KINDS OF SURE EVIDENCE OF THE GREAT MAGMA CHAMBER UNDER YELLOWSTONE.

BUT FUMERALS ARE FOUND ALL OVER THE WORLD.

GEYSERS ARE FOUND ONLY IN A VERY FEW PLACES.

THIS IS THE FOUNTAIN PAINT POT.

IT HAS ALL THESE DIFFERENT COLORS BECAUSE IT'S A LABORATORY OF NATURE.

THERE ARE ACTUALLY MICROORGANISMS HERE THAT EAT THE HYDROGEN SULFITE GAS AS IT COMES OUT WHICH IS A DEADLY POISON, NOT MADE GAS.

THEY CONVERT IT TO SULFURIC ACID WHICH ACTS ON THE MUD TO MAKE DIFFERENT COLORS THERE AND DIFFERENT KINDS OF ORGANISMS IN DIFFERENT PARTS OF IT ACTUALLY GIVE DIFFERENT COLORS.

IT'S A MICROCOSM OF MICROORGANISMS HERE IN YELLOWSTONE.

IT'S HARD TO BELIEVE WE SEE EVOLUTION IN ACTION HERE IN A POT.

THE WATER COMING OUT OF SILEX SPRING IS TOO HOT TO SUPPORT MANY MICROORGANISMS BUT AS IT COOLS IT BEGINS TO PRODUCE THIS SPECTRUM OF BACTERIA, OF STRANGE TINY ORGANISMS THAT THEN GIVE RISE TO A FLY AND IF YOU LOOK VERY CLOSELY, AND I CAN SEE THEM HERE, HERE WE ARE IN THE MIDDLE OF WINTER, HERE ARE FLIES LIVING IN THIS WARM WATER.

MICROBIOLOGISTS HAVE DISCOVERED THAT THE ENZYMS GIVEN OFF OF ONE STRAIN OF THIS BACTERIA ARE A CRITICAL ELEMENT IN LABORATORY CHEMISTRY, PARTICULARLY IN DNA ANALYSIS.

SO IMPORTANT THAT ITS DISCOVERER EARNED A NOBEL PRIZE.

ELK OVER THERE RIGHT BY THE EDGE OF THE RIVER.

YOU CAN SEE THE STEAM COMING OUT OF THEIR NOSES.

TEMPERATURE IS ABOUT 13 DEGREES.

BRING THEM IN A LITTLE BIT MORE.

THEY PAW AT THE SNOW TO GET ACCESS TO THE GRASS.

IT'S NOT UNUSUAL FOR AN ELK TO WEIGH 1,000 POUNDS, PARTICULARLY AT THE END OF SUMMER.

THE TEMPERATURE OF THE WATER TENDS TO MAKE IT A LITTLE BIT EASIER FOR THE SNOW, IT DOESN'T QUITE GET AS THICK BECAUSE THERE'S THE HEAT EFFECT FROM THE RIVER.

LOOK AT THAT STEAM RISING OUT.

THE STEAM WILL COME OUT OF THE WATER BECAUSE IT'S RIGHT NOW 32, 33 DEGREES AND THE AMBIENT TEMPERATURE IS ABOUT 13 OR 14 DEGREES.

IN SOME PLACES THERE WILL BE HYDROTHERMAL ACTIVITY WHICH WILL MEAN LITTLE GEYSERS AND THEN WHEN YOU HIT AREAS OF RAPIDS, THE WATER WILL TURN OVER AND RELEASE SOME MORE OF ITS HEAT.

THIS PARTICULAR HOT SPRING IS MOST UNUSUAL.

THE HOT WATER, AS IT COMES TO THE SURFACE, PASSES THROUGH AN IRON RICH STRATUM AND IT DISSOLVES IRON.

WHEN IT REACHES THE SURFACE, IT COOLS OFF AND DEPOSITS THAT IRON AND SO WE SEE THE REDDISH COLOR.

BUT RECENTLY SCIENTISTS HAVE DISCOVERED THERE ARE A NUMBER OF MICROORGANISMS LIVING ON THAT ROCK THAT EAT IRON.

THESE KIND OF BACTERIA MAY BE A CLUE TO WHAT'S HAPPENING ON OTHER PLANETS.

HERE WE HAVE THE BEGINNINGS OF YELLOWSTONE NATIONAL PARK OF ASTRO-BIOLOGY.

THE LAST TIME I VISITED YELLOWSTONE NATIONAL PARK WAS IN 1947.

I WAS SIX YEARS OLD.

THE ONE THING I REMEMBER FROM THAT TRIP WAS OLD FAITHFUL GEYSER.

IT WAS FAITHFUL THEN, IT'S FAITHFUL NOW AND IT'S SET TO GO OFF ANY TIME.

OLD FAITHFUL'S ERUPTIONS LAST FROM A MINUTE TO FIVE MINUTES.

THE STEAM REACHES 106 TO 180 FEET HIGH AND THE ERUPTIONS OCCUR EVERY 60 TO 90 MINUTES.

WE KNOW THAT IT'S BEEN ERUPTING FOR AT LEAST 130 YEARS.

IT WAS FIRST, IN WRITTEN DESCRIPTION, CAME TO US FROM SOME EARLY ARRIVALS OF EUROPEAN EXTRACTION IN 1870.

IT PROBABLY HAS BEEN GOING ON A MUCH LONGER TIME, PROBABLY OVER 1,000 YEARS.

OF THE 900 KNOWN GEYSERS IN THE WORLD MORE THAN HALF OF THEM ARE IN YELLOWSTONE NATIONAL PARK.

THIS HILL IS CALLED GEYSER HILL.

IT'S IN OLD FAITHFUL'S BACKYARD.

ON THIS HILL ALONE THERE ARE 30 GEYSERS.

WITHIN A TWO MILES RADIUS THERE ARE 150 WHICH REPRESENTS ABOUT 20 PERCENT OF ALL THE GEYSERS IN THE WORLD.

IF YOU WANT TO SEE GEYSERS, THIS IS THE PLACE.

THIS ONE HERE IS CALLED THE ANEMONE AND WELL NAMED AND IT LOOKS AS THOUGH IT'S JUST ABOUT TO POP.

I SEE GURGLES, I SEE WATER.

THERE IT COMES.

MANY OF THE GEYSERS HAVE PERSONALITIES TO FIT THEIR NAMES OR MAYBE THE OTHER WAY AROUND.

THIS IS PUMP GEYSER.

IT SEEMS TO PUMP STEAM OUT REGULARLY.

IT'LL STOP START AGAIN AND THE PUMPING SOUND THAT IT MAKES GAVE IT ITS NAME.

OVER HERE IS TEA KETTLE.

IT SORT OF LOOKS LIKE A TEA KETTLE, MAYBE ACTS LIKE ONE.

BEATS ME.

OVER HERE IS THE LION WHICH IS NAMED BECAUSE IT ROARS.

IT'S THE ONLY PLACE ON EARTH WHERE YOU CAN SEE SO MANY GEYSERS, SO MANY DIFFERENT TYPES OF GEYSERS, SO MUCH VOLCANIC ACTIVITY IN ONE SMALL PLACE.

WELL, THIS IS YURT CAMP AND YOU MUST BE ARDEN.

HI, I'M ARDEN.

AND YOU'RE DAVID.

SORRY TO INTERRUPT YOUR WORK.

NICE TO MEET YOU.

OH, JUST SPLITTING SOME FIREWOOD FOR TONIGHT.

YEAH, MY HANDS ARE WARMER THAN YOURS.

THESE LOOK LIKE YURTS.

THIS IS THE KITCHEN AND THE DINING ROOM AND THEY'RE REGULAR OLD YURTS MODELED AFTER THE MONGOLIAN YURTS ALTHOUGH WE MADE THE PEAKS A LITTLE STEEPER BECAUSE WE HAVE ACTUALLY MORE SNOW HERE THAN IN... YEAH, THEY DON'T GET A LOT OF SNOW IN MONGOLIA.

RIGHT.

EXACTLY.

WITH THAT INLAND STUFF.

AND THEN THESE COMING DOWN THIS DIRECTION IS WHERE YOU'LL BE SLEEPING AT NIGHT IN WHAT WE CALL A YURT-LET.

YURT-LET, THAT'S A GOOD IDEA.

I GREW UP IN MINNESOTA SO KIND OF MODELED THEM AFTER ICE FISHING HOUSES IF YOU EVER SAW THE MOVIE GRUMPY OLD MEN , THAT KIND OF THING.

I GUESS I WAS PROBABLY ONE OF THOSE.

WELL, HOW DO YOU HEAT THEM?

THEY'RE HEATED WITH PROPANE EATERS.

OKAY.

AND IF YOU WANT TO SET THAT THING AT 80 DEGREES IT'LL STAY 80 DEGREES IN THIS.

IS THAT RIGHT?

WELL, I UNDERSTAND IT'S SUPPOSED TO GET DOWN TO AT LEAST 10 BELOW TONIGHT SO I'M IN FAVOR OF SOME HEATING.

SO I THINK THE COLDEST TEMPERATURE IN YELLOWSTONE IS LIKE 67 BELOW AND THE CLEARER IT IS THE COLDER IT'LL GET.

WE'RE RIGHT INSIDE THE PARK HERE.

IS THIS NORMAL DEPTH OF SNOW?

AH, IT DEPENDS SO MUCH ON THE YEAR.

ON A NORMAL YEAR, WHATEVER NORMAL IS, 40 TO 50 INCHES OF SNOW ON THE GROUND BY FEBRUARY.

LAST YEAR WE HAD ALMOST 80 INCHES.

WHEN ERICA AND I CAME IN HERE LATE IN THE SPRING TO JUST SHOVEL WE ACTUALLY WALKED OVER THE TOP OF THIS HOUSE WITH OUR SNOWSHOES.

IT'S KIND OF HARD TO GET IN THE DOOR THAT WAY.

IT WAS.

WE HAD TO SHOVEL QUITE A BIT.

I'M GLAD TO SEE YOU HAVE A GOOD WOOD PILE.

ALL RIGHT, THAT'S MY WORK FOR THE DAY.

OKAY.

8,000 FEET.

NO AIR TO BREATHE.

WATCH THAT HEAD AGAIN.

YEAH, THANK YOU.

I'VE ALREADY HIT IT ONCE.

BUT TO GET EVERYTHING OUT FROM THE YURT CAMP LAST YEAR I WAS FINALLY ABLE TO DRIVE IN HERE TO THE CAMP ON THE 19TH OF JUNE.

OH, MY GOODNESS.

THAT'S WHEN THE LAST OF THE SNOW MELTED ENOUGH FOR ME TO GET UP HERE.

THAT'S ABOUT THE SAME TIME IN TUCSON THAT WE REACH 100 DEGREES.

WE'RE GOING TO GO DOWN TO THE UPPER FALLS OF THE YELLOWSTONE RIVER.

THERE'S A BEAUTIFUL LITTLE TRAIL ALONG THE RIVER THERE I THINK AND SOME NICE MEADOWS AND SOME FORESTS SO A GOOD COMBINATION OF THINGS TO TAKE A LOOK AT.

STRAIGHT AHEAD HERE IS LOOKING OUT TOWARDS HAYDEN VALLEY.

OKAY.

IT'S AN OLD GLACIAL LAKEBED AND WHEREVER YOU HAVE LAKE SEDIMENTS THE TREES DON'T GROW.

YEAH.

TYPICALLY IN YELLOWSTONE WHERE THE CALDERA IS, WHERE YOU HAVE THE LAVA FLOWS THAT ARE HIGH IN SILICA, YOU HAVE LODGEPOLE PINE FORESTS.

WHERE YOU HAVE THE ANDESITE VOLCANIC FROM OLDER VOLCANISM YOU HAVE HIGHER CALCIUM CONTENTS AND OTHER MINERALS AND YOU HAVE FIR AND SPRUCE TREES, ELEVATION MATTERS A LITTLE BIT ALSO.

YEAH, UH HUH.

AND THEN WHERE YOU HAVE STREAM DEPOSITS OR LAKE DEPOSITS YOU HAVE MEADOWS.

THE YELLOWSTONE RIVER IS THE LONGEST UNDAMMED RIVER IN THE UNITED STATES.

IT STARTS JUST SOUTH OF THE PARK, GOES ALL THE WAY TO THE BORDER OF NORTH DAKOTA, 700 MILES FREE FLOWING.

AND THEN IT BECOMES THE MISSOURI.

AND IT FLOWS INTO THE MISSOURI, RIGHT.

AND DIDN'T LEWIS AND CLARK COME WAY UP HERE?

THEY DID.

THEY HIT THE YELLOWSTONE FURTHER DOWN FROM HERE, DOWNSTREAM AND ACTUALLY I THINK A GOOD THING THAT THEY DIDN'T COME HERE BECAUSE IN 1800 I DON'T THINK THE MOOD OF THE COUNTRY WAS RIGHT TO SET ASIDE A NATIONAL PARK.

SO WE'RE SEEING IT HOW FAR FROM ITS ORIGINS RIGHT HERE?

WE'RE 16 MILES DOWNSTREAM FROM YELLOWSTONE LAKE.

REMEMBER, THIS IS WINTER.

IN THE SUMMERTIME THERE'D BE ALMOST 10 TIMES AS MUCH FLOW.

10 TIMES AS MUCH FLOW?

OH, MY GOODNESS.

YOU CAN SEE THE MOUNTAINS THERE TOO.

THAT'S THE EDGE OF THE CALDERA SO WE'RE... WE'RE IN THE MIDDLE OF THE CALDERA RIGHT HERE.

YOU'RE IN IT.

YEAH, THE BIGGEST...THE THROE TO THE BIGGEST VOLCANO ON EARTH.

BENEATH US IS A MAGMA CHAMBER OF UNIMAGINABLE PROPORTION.

HMM MM.

IF IT WERE TO BLOW, WE WOULD PROBABLY NOT SEE IT.

BUT THEY MIGHT GET THE EFFECTS IN TENNESSEE.

YOU'D PROBABLY RATHER BE HERE AND JUST BE DONE WITH THAN TO HAVE TO SUFFER THE NUCLEAR WINTER LATER.

A SLOW DEATH, YEAH.

YEAH.

AND IT WOULD AFFECT THE CLIMATE OF THE EARTH FOR DECADES OR EVEN CENTURIES TO COME.

AND THE OTHER PART I THINK THAT GOES WITH THAT IS THAT WE'VE MEASURED THAT IT GOES UP AND DOWN A LITTLE BIT.

IT'LL BULGE UP, THE MAGMA WILL CRYSTALLIZE AND SHRINK, IT'LL BULGE UP AS MORE MAGMA IS INJECTED UNDER YOUR FEET.

AND WHAT IS HAPPENING RIGHT NOW?

WE'RE GOING ABOUT THE SPEED THAT YOUR THUMBNAIL GROWS.

YEAH.

OKAY.

THAT'S GOOD TECTONIC MOVEMENT.

YEAH.

I'M GOING TO ASSUME THAT WE'RE SAFE TO GO SNOWSHOEING WITHOUT WORRYING TOO MUCH ABOUT IT.

I THINK THE SNOW WILL START TO MELT JUST BEFORE IT GOES.

JUST BEFORE IT GOES.

OKAY, I'LL WATCH FOR THE MELT.

THIS'LL BE A LITTLE MORE WORK NOW, DAVID.

THIS IS A TAD MORE.

YOU DO SINK IN BUT NOT AS MUCH AS WITHOUT THEM.

BUT WHAT WE WANT TO WATCH FOR HERE IS OTTERS.

AND I KNOW THERE ARE BALD EAGLES HERE.

YES.

SO THE OTTERS ARE FISHING ALL YEAR ROUND THEN.

THEY DON'T SLOW DOWN, HUH?

NO, THEY STILL ARE LOOKING FOR FISH.

THERE HAVE BEEN RECORDED INSTANCES OF WOLVERINES AND FISHERS.

HAVE YOU EVER SEEN A WOLVERINE?

I'VE SEEN ONE WOLVERINE AND IT WASN'T IN YELLOWSTONE.

REALLY?

THAT'S MY GOAL SOMEDAY.

JUST UP IN THE BEAR TOOTH MOUNTAINS JUST NORTHEAST OF HERE.

UH HUH.

THIS IS WORK, ISN'T IT?

YEAH.

I'VE HAD WORSE WORK.

I WAS SITTING AT A DESK.

I LIKE THIS BACKYARD.

THIS SNOW IS FAIRLY DEEP.

THIS IS A 40 FOOT HIGH LODGEPOLE PINE RIGHT HERE.

RIGHT.

JUST THE TOP, RIGHT?

THAT'S RIGHT.

SO HOW HAS IT CHANGED IN THE LAST 24, 25 YEARS HERE FOR WINTER VISITATION?

SINCE I'VE BEEN HERE, PROBABLY MORE SNOW COACH RIDERS AND SNOWSHOERS.

THE 4-STROKE SNOWMOBILES I THINK HAVE BEEN REALLY NICE.

THEY'RE MUCH QUIETER.

OH, GOSH, THEY'RE SO QUIET.

AND THEY DON'T POLLUTE AS MUCH.

AND THEY DON'T POLLUTE NEARLY AS MUCH.

YEAH, THEY'RE REQUIRED TO STAY ON A ROADWAY JUST LIKE WE ARE IN OUR SNOW COACH AND THEN THAT LEAVES TWO MILLION ACRES OF BACK COUNTRY LIKE THIS FOR US TO GO SNOWSHOEING IN.

WHAT CHANGE HAVE YOU SEEN AS THE EFFECT OF THE INTRODUCTION OF THE WOLVES?

WITHOUT PREDATORS HERE THE ELK WERE REALLY MAYBE EVEN OVER POPULATED AND SO PROBABLY A BALANCE.

AND IT'S KIND OF INTERESTING YOU INTRODUCE THE WOLF AND THE WOLF NUMBERS WENT UP DRAMATICALLY, THE ELK NUMBERS DROPPED DOWN, NOW THE WOLVES HAVE KIND OF USED UP SOME OF THAT FOOD SUPPLY AND THEY'RE STARTING TO OSCILLATE NOW A LITTLE BIT SO YOU PROBABLY HAVE REACHED THAT EQUILIBRIUM.

AMAZING, YEAH, EQUILIBRIUM.

THAT'S INTERESTING.

IN THE SUMMERTIME WE'LL SEE LOTS OF ELK AROUND THE CANYON AREA HERE.

IN THE WINTERTIME NOT SO MUCH BECAUSE THE SNOW'S TOO DEEP.

I THINK YOU'RE HAVING THE SAME PROBLEM.

YOU KNOW, I THINK THE SNOW'S A LITTLE DEEP FOR ME.

LET ME SEE IF I CAN PULL MY SNOWSHOE OUT OF HERE.

NOW THE SNOWSHOES KEEP YOU FROM GOING WAY DOWN IN, RIGHT?

RIGHT.

YEAH, UH HUH.

THERE'S ONE FOOT UP AND... YOU KNOW, IF YOU GET STUCK YOU CAN ALWAYS PLAY BISON AND STICK YOUR FACE IN THE SNOW.

I'LL USE THOSE POWERFUL NECK MUSCLES TO SWEEP THE SNOW ASIDE.

I'M GOING TO STAY OUT OF THE REALLY DEEP DRIFTS AND CONFINE IT TO THREE OR FOUR FOOT DEEP.

YEAH.

JUST FOLLOW THIS BISON TRAIL AND IT MAKES IT A LOT EASIER BREAKING TRAIL.

THE BULLS OFTEN JUST KIND OF GO OFF ON THEIR OWN.

I THINK OF IT AS THEY'RE HEADED FOR THE MOUNTAIN MAN CAVE OF THE BISON OR SOMETHING.

I SEE, WHERE THEY HAVE THEIR BONDING CEREMONIES THEN.

RIGHT.

MOST PEOPLE THINK THAT THE PARKS WERE STARTED BY THEODORE ROOSEVELT.

YEAH.

THE ACTUAL ENABLING LEGISLATION FOR YELLOWSTONE WAS SIGNED BY ULYSSES GRANT.

U. S. GRANT, YEAH.

BUT THIS IS THE FIRST NATIONAL PARK IN THE WORLD, AN IDEA THAT YOU COULD SET ASIDE CHUNKS OF LAND FOR THE GENERAL POPULATION IS UNIQUELY AMERICAN.

THEY SET ASIDE THIS PARK BECAUSE THE GEYSERS, THE CANYON, THE FOREST, THE WILDLIFE.

NOBODY HAD ANY IDEA THAT IT WAS ALSO THE WORLD'S BIGGEST MAGMA TUBE.

PROBABLY NOT.

IT WAS REALLY ONLY AFTER WE STARTED SEEING THINGS FROM SPACE.

WE KEPT SEEING ALL THESE VOLCANIC LAVA FLOWS AND GOING, 'WHERE IS THE VOLCANO?'

AND THEN VISIONS FROM SPACE WOULD SAY, 'OH, WAIT, IT'S ALL A BIG VOLCANO.'

AND NOBODY COULD COMPREHEND ANYTHING THAT VAST.

WHAT IS IT, 50 MILES ACROSS?

WHAT, 30 MILES ACROSS BY 40 MILES LONG.

IT'S UNTHINKABLY BIG.

OH, IT'S BIGGER THAN SOME STATES.

YEAH.

SO WE'RE FOLLOWING THE RIVER HERE.

THIS DOESN'T LOOK LIKE A CANYON BECAUSE THERE'S SO MUCH SNOW.

IT'S GOING TO BE JUST OVER THE HILL HERE.

IT FIRST GOES OVER 109 FOOT WATERFALL AND THEN JUST AROUND THE CORNER AFTER THAT A 308 FOOT WATERFALL.

DOES IT EVER GET COLD ENOUGH HERE FOR THE RIVER TO FREEZE?

THE YELLOWSTONE WILL FREEZE OVER.

THE FIREHOLE RIVER WHERE THAT HOT WATER COMES OUT OF OLD FAITHFUL DOESN'T FREEZE BUT THIS RIVER WILL FREEZE ON THE COLDEST, COLDEST TIME OF THE WINTER.

WELL, IT WAS ZERO THIS MORNING AND THAT'S NOT ENOUGH, HUH?

DO YOU WANT ME TO BREAK TRAIL FOR AWHILE?

I ACCEPT YOUR OFFER TO...ALL RIGHT, YOU BREAK THE PATH.

I'LL LET YOU GO BY BECAUSE I'M A NICE GUY.

OKAY.

THIS IS DEEPER THAN IT WAS BEFORE.

I THINK IT'S SNOWED A FOOT SINCE WE STARTED.

IT'S HARD TO PICK ONE SPOT OVER ANOTHER.

I MEAN, LOOK AT THIS.

I'VE SEEN UGLIER PLACES.

IT'S NOT A BAD BACKYARD.

NOW IS THAT MOSTLY FROZEN NOW?

THE BOTTOM PART IS FROZEN AND IF YOU LOOK AT THE RIGHT HAND SIDE, IT'S FROZEN.

BUT THE LEFT HAND SIDE AS WE LOOK AT IT IS STILL RUNNING WATER.

IT'S ACTUALLY 308 FEET HIGH AND TO PUT THAT IN PERSPECTIVE THAT'S NEARLY TWICE AS HIGH AS NIAGARA FALLS.

AS NIAGARA, YEAH.

NOT AS WIDE BUT TWICE AS HIGH.

HOW COLD DOES IT HAVE TO BE FOR THE WHOLE THING TO FREEZE?

I'VE NEVER SEEN THE WHOLE THING FROZEN.

THERE'S ALWAYS A LITTLE BIT OF WATER RUNNING ON THAT LEFT SIDE.

NOW THERE'S A TOTAL ICE BRIDGE OVER THE TOP AND THAT'S JUST SPRAY THAT FREEZES AND FREEZES AND FREEZES.

SO THERE'S NOT MUCH EROSION GOING ON THERE THEN.

I DON'T KNOW.

YEAH, IN THE WINTER IF THERE IS MUCH AT ALL BUT IT SURE BUILDS A BIG ICE CONE.

SO IF I GET HERE IN THE ICE MELT IN JUNE OR WHENEVER IT IS I'M GOING TO SEE A LOT MORE WATER COME OVER.

YOU PROMISED ME THE BIG PICTURE AND NOW I GET IT AND THAT'S THE YELLOWSTONE CALDERA.

YEAH, WE'RE RIGHT HERE ON THE NORTHERN EDGE OF THE CALDERA AND IT ACTUALLY GOES QUITE A WAYS EVEN FURTHER TO THE EAST HERE AND IT'S THAT HOT ROCK STILL UNDERNEATH THERE THAT POWERS ALL THESE GEYSERS AND HOT SPRINGS BASINS THAT WE SEE OUT IN FRONT OF US.

YEAH.

THIS IS THE MOST CONCENTRATED AREA OF GEYSERS AND HOT SPRINGS ANYWHERE.

SO I'D LIKE TO THANK THE CONGRESS AND PRESIDENT OF THE UNITED STATES IN 1872 IN MAKING SURE I HAVE A CHANCE TO SEE IT.

ISN'T IT NICE?

YEAH.

MEXICO, ESPECIALLY IN THE SOUTH, IS HOME TO A WIDE VARIETY OF INDIAN LANGUAGES.

IN THE REMOTE CLOUD FOREST IN THE MOUNTAINS OF THE STATE OF OAXACA, NATIVE PEOPLE SPEAK TONAL LANGUAGES.

[MUSIC] [MUSIC] FUNDING FOR IN THE AMERICAS WITH DAVID YETMAN WAS PROVIDED BY AGNES HAURY.

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