Bitter cold arctic air settled over parts of Wyoming. Overnight temperatures fell to 25 to 35 below zero (-36 in Grant Village of Yellowstone National Park) on the 12th.
Every event with a place to put it; 7 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS RIW wrote it up.
Bitter cold arctic air settled over parts of Wyoming. Overnight temperatures fell to 25 to 35 below zero (-36 in Grant Village of Yellowstone National Park) on the 12th.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Riverton, WY wrote its last area forecast discussion before the first event at Feb 11, 2:30 PM MST, 3 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 230 PM MST WED FEB 11 2004 .TONIGHT THROUGH SATURDAY... SOME LINGERING LIGHT SNOW SHOULD OCCUR IN SOUTHERN WY AND ALONG THE SOUTHERN EAST SLOPES OF THE WIND RIVER MTNS EARLY THIS EVENING AS THE POSITIVELY TILTED TROUGH NOW EXTENDING FROM SOUTH DAKOTA TO UTAH CONTINUES TO EXIT TO THE SOUTH SOUTHEAST AND THE CIRCULATION EVIDENT OVER WY BEGINS TO SHEAR APART. BACK EDGE OF THE CLOUDS APPEARS TO BE AS FAR SOUTH AS THE OWL CREEK MTNS. NEXT THE FOCUS TURNS TO A WIDESPREAD FOG EVENT AFFECTING MOST OF THE WESTERN AND CENTRAL BASINS AND VALLEYS DURING THE NEXT 3 NIGHTS/MORNINGS. CLASSIC FOG SYNOPTIC SCENARIO SETTING UP AT THE MOMENT AS THE RIDGE ALONG THE PACIFIC COAST IS NOW BUCKLING TOWARD THE EAST OVER CANADA ON TOP OF THE EXITING TROUGH. THIS MEANS WARM AIR ADVECTING IN ALOFT FROM THE NORTH WITH H7 TEMPS WARMING FROM -20C TO -3C OVER CENTRAL WY BY 00Z SAT. LOWER ELEVATIONS OF SWEETWATER COUNTY AS WELL AS THE UPPER GREEN/WIND RIVER BASINS WILL HAVE PATCHY FOG TONIGHT/THU AM WITH MORE EXTENSIVE AREAS OF FOG FARTHER NORTH OVER THE BIG HORN BASIN AND THE STAR AND JACKSON VALLEYS WHERE RADIATIONAL WILL HAVE A HEAD START WHERE SKIES ARE ALREADY MOSTLY CLEAR AND SNOW COVER IN PLACE...NOT TO MENTION 1042 SFC HIGH RIGHT OVERHEAD. FOG SHOULD BE MORE WIDESPREAD OVER THE WESTERN AND CENTRAL BASINS/VALLEYS THURSDAY NIGHT/FRIDAY MORNING. THE COLDEST MORNING OF THE FORECAST PERIOD SHOULD BE THURSDAY MORNING MOST AREAS WITH THE WESTERN BASINS/VALLEYS BOTTOMING OUT CLOSE TO 20 BELOW IN SOME PIT AREAS. TEMPS WILL WARM UP INTO THE HIGH 20S THURSDAY AND THEN INTO THE UPPER 30S FRIDAY IN THE SOUTHERN WIND CORRIDOR AS A LEE SIDE TROUGH BECOMES ESTABLISHED WITH RESULTING WEST SOUTHWEST WINDS WITH TEMPS WARMING THERE AS A RESULT. TEMPS IN THE BASINS WILL LAG BEHIND WITH HIGHS STILL IN THE 20S FRIDAY AND THEN CREEPING INTO THE 30S BY SATURDAY. THE RIDGE WILL BREAK DOWN SATURDAY AND THE NEXT PACIFIC TROUGH WILL BRING SOME LIGHT SNOW TO THE FAR WEST BY SATURDAY AFTERNOON. .SATURDAY THROUGH THURSDAY... THE SHORT WAVE IS MORE PROGRESSIVE THAN THE GFS WAS INDICATING LAST NIGHT. WILL GO WITH CHC POPS ACROSS CWFA SATURDAY NIGHT AND SLGT CHC TO CHC POPS ACROSS NORTH AND EAST CWFA ON SUNDAY. GOING WITH A DRY FORECAST FOR SUNDAY NIGHT THROUGH WEDNESDAY AS UPPER HEIGHTS REBUILD. TEMPS SHOULD REMAIN AROUND SEASONABLE READINGS THROUGH THE EXTENDED FORECAST...HOWEVER HIGHS IN THE 40S ACROSS JOHNSON AND NATRONA COUNTIES BY TUESDAY AND WEDNESDAY. && .RIW WATCHES/WARNINGS/ADVISORIES...NONE. && LIPSON/MC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 822 AM MST WED FEB 11 2004 WYZ001>020-022>030-121200- ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST- BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS- EAST SWEETWATER COUNTY-FLAMING GORGE- GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS- NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN- NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS- ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES- SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN- SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY- TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN- UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN- WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST- YELLOWSTONE NATIONAL PARK- 822 AM MST WED FEB 11 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. ...BLIZZARD WARNING FOR NORTHEAST JOHNSON COUNTY THIS MORNING... .DAY ONE...TODAY AND TONIGHT BLIZZARD CONDITIONS WILL OCCUR THIS MORNING IN NORTHEAST JOHNSON COUNTY. ELSEWHERE 5 TO 7 INCHES OF SNOWFALL IS EXPECTED IN THE LANDER FOOTHILLS ALONG WITH 1 TO 3 INCHES OF SNOWFALL AND LOCALLY UP TO 5 INCHES EXPECTED IN THE WIND RIVER BASIN. LESSER AMOUNTS OF SNOWFALL ARE EXPECTED ELSEWHERE THIS MORNING...MAINLY EAST OF THE DIVIDE. OTHERWISE LINGERING LIGHT SNOW WILL TAPER OFF LATER THIS AFTERNOON. HOWEVER...NORTHWEST TO NORTH WINDS OF 20 TO 30 MPH GUSTING TO 40 MPH WILL CONTINUE TO CAUSE BLOWING AND DRIFTING SNOW IN JOHNSON COUNTY AND IN THE BIG HORN MOUNTAINS. THE VISIBILITY WILL BE REDUCED TO LESS THAN ONE HALF MILE AT TIMES ACROSS NORTHEAST JOHNSON COUNTY...INCLUDING BUFFALO DURING THE MORNING HOURS. THE WINDS WILL GRADUALLY TAPER OFF AS THE DAY PROGRESSES. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS TO THE NATIONAL WEATHER SERVICE IN RIVERTON TODAY. THANK YOU. LIPSON
The national radar mosaic for the moment the first event began.
7 cold/wind chill. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2004Every state in 2004This day in weather historyWarnings in Wyoming, February 2004
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5382490, 5382491, 5382492, 5382493, 5382494, 5382495, 5382496.