Heavy Snow in Wyoming, May 2 to 3, 2001

Name: Heavy Snow in Wyoming, May 2 to 3, 2001
Start: 2001-05-02T16:00
End: 2001-05-03T16:00
Location: Wyoming

May 2 to 3, 2001 · NWS RIW · 3 events in 3 counties and zones

with up to a foot and a half of new snow locally along the north foothills area of the Uinta Mtns.

Where it happened

Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 3

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.

What happened

The episode as NWS RIW wrote it up.

Around a foot of new snow in the Wind River Mtns...with up to a foot and a half of new snow locally along the north foothills area of the Uinta Mtns.

What forecasters said that day

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 May 2, 1:53 PM MST, 2 hours 7 minutes earlier.

Area forecast discussion, May 2, 1:53 PM MST, 2 hours 7 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
253 PM MDT WED MAY 2 2001

WATER VAPOR LOOP SHOWS AMPLIFYING TROUGH EASTERN IDAHO ACROSS
UTAH/NEVADA BORDER.  UPPER DIVERGENT AREA WELL DEFINED WITH
ENHANCED CLOUD BAND FROM SOUTHERN UTAH THROUGH THE SOUTHEAST HALF OF
WYOMING.  AT THE SURFACE...MAX PRESSURE FALLS ACROSS NW NEW MEXICO
WITH 997 MB SURFACE LOW JUST TO THE WEST.  WEDGE OF UPSLOPE CLOUDS
HAVE FORMED ALONG THE EASTERN WIND RIVER MOUNTAINS WITH LIGHT SNOW
BEGINNING TO FALL.  ETA HAS DONE WELL SO FAR WITH AREAS OF UPPER
DIVERGENCE AND SURFACE FIELDS AND PREFER IT TO AVN IN EVENT
WHERE OROGRAPHICS WILL HAVE A SIGNIFICANT INFLUENCE ON
PRECIPITATION.  INITIAL H7 LOW FORMS SOUTH OF VEL TONIGHT WITH
INCREASING NORTHEAST FLOW BELOW 10KFT AGL.  AREA OF UPPER
DIVERGENCE TO BACK MORE INTO SOUTHWEST AND CENTRAL WYOMING TONIGHT
AS TROUGH SHARPENS.  THESE TWO FACTORS WILL BE VERY FAVORABLE FOR
SNOW MAINLY SOUTH OF A KMM TO CPR LINE.  CASPER (NORTH END OF
LARAMIE RANGE) THE LANDER FOOTHILLS...GREEN MTNS AND SOUTHERN PART
OF SWEETWATER WILL RECEIVE THE MOST SNOWFALL WHERE OROGRAPHICS WILL
COME INTO PLAY.  WINDS ALSO PROGGED TO INCREASE SUBSTANTIALLY
ACROSS THE SOUTHWEST WHERE ALL GUIDANCE INCLUDING MESO-ETA BOUNDARY
LAYER WINDS SHOW SUSTAINED NE WINDS AROUND 40 KTS THROUGH EARLY
THURSDAY.  WILL GO WITH A WINTER STORM WARNING IN ABOVE MENTIONED
AREAS WITH AMOUNTS GENERALLY BETWEEN 4 AND 8 INCHES BY MIDDAY
THURSDAY WITH 8 TO 12 IN EASTERN WIND RIVER MTNS.  SNOW AND BLOWING
SNOW ADVISORY WILL SUFFICE FOR ZONES 13 AND 18 WHERE OROGRAPHICS
WILL NOT FACTOR IN AS MUCH.  TO NORTH AND WEST...DRIER AIRMASS AND
LESS LIFT WILL RESULT LIGHTER AMOUNTS NORTHEAST WITH NIL OR LOW
SCATTERED POPS WEST OF DIVIDE.  UPPER LOW SINKS FURTHER SOUTH
THURSDAY TAKING DYNAMICS INTO MAINLY COLORADO AND SOUTHEAST
WYOMING.  UPSLOPE SNOWS SHOULD TAPER OFF AROUND MIDDAY AS HEATING
AND SLIGHT INSTABILITY BEGIN TO SHUTDOWN SEEDER/FEEDER STRATIFORM
MECHANISM.  CPR AND SW ZONES WILL CONTINUE TO BE ON NORTHERN FRINGE
OF DYNAMICS WHERE LIGHT SNOW WILL CONTINUE INTO AFTERNOON.   AGREE
MORE WITH ETA SOLUTION MOVING UPPER LOW SLOWLY OUT OF SOUTHERN
ROCKIES RATHER THAN AVN SPLITTING LOW ACROSS WESTERN WYOMING FRIDAY
NIGHT.  IN EXTENDED...12Z AVN DIVERGING FROM LAST NIGHTS MRF SO NOT
A LOT OF CONFIDENCE BEYOND FRIDAY.  WILL GENERALLY KEEP AFFECTS OF
TROUGH AND SUBSEQUENT KICKER SYSTEM TO FOLLOW IN THROUGH MONDAY WITH
CHANCE POPS AND COOL TEMPERATURES. THEN UPPER RIDGE BUILDS IN
TUESDAY AND WEDNESDAY FOR WARMER DRIER WEATHER.

.RIW...WINTER STORM WARNING TONIGHT INTO THURSDAY PARTS
       OF CENTRAL AND SOUTHWEST   ZNS 11..12..14..15..22>25.
       SNOW AND BLOWING SNOW ADVISORY TONIGHT INTO THURSDAY
       ZNS 13..18.

AEM

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 heavy snow. Local standard time, as filed.

Heavy Snow, Lander Foothills / C Fremont

When: May 2, 4:00 PM MST to May 3, 3:00 PM MST
Where: Lander Foothills / C Fremont forecast zone
Reported by: NWS EMPLOYEE(OFF DUTY)
Coordinates: 43.002, -109.948 (the zone’s center; the record gives no point)

Heavy Snow, Rock Springs/Green River / Sw Sweetwater

When: May 2, 4:00 PM MST to May 3, 4:00 PM MST
Where: Rock Springs/Green River / Sw Sweetwater forecast zone
Reported by: TRAINED SPOTTER
Coordinates: 42.962, -106.798 (the zone’s center; the record gives no point)

Heavy Snow, Wind River Mtns East / Wc Fremont

When: May 2, 4:00 PM MST to May 3, 3:00 PM MST
Where: Wind River Mtns East / Wc Fremont forecast zone
Reported by: TRAINED SPOTTER
Coordinates: 44.039, -106.585 (the zone’s center; the record gives no point)

What these are

Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Wyoming in 2001 Every state in 2001 This day in weather history Warnings in Wyoming, May 2001

Sources

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: 5244936, 5244937, 5244938.