Heavy Snow in Wyoming, May 11 to 12, 2010

Name: Heavy Snow in Wyoming, May 11 to 12, 2010
Start: 2010-05-11T11:00
End: 2010-05-12T13:40
Location: Wyoming

May 11 to 12, 2010 · NWS CYS · 29 events in 14 counties and zones

Where it happened

Every event with a place to put it; 29 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: 29

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 CYS wrote it up.

During the evening of the 11th widespread rainfall developed across the area. As cold air was brought into the region by a strong upper level storm system over the area, the temperature fell below the freezing point causing the rain to change over to snow. Due to the abundant moisture present, widespread heavy snowfall developed across the area during the early morning hours of the 12th. Interstate 80 and Happy Jack Road were closed for a few hours during the early morning of the 12th due to blowing snow.

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 Cheyenne, WY wrote its last area forecast discussion before the first event at May 11, 4:58 AM MST, 6 hours 2 minutes earlier.

Area forecast discussion, May 11, 4:58 AM MST, 6 hours 2 minutes before

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Hazardous weather outlook, May 11, 9:45 AM MST, 1 hour 15 minutes before

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The radar

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

Open the radar archive at this moment

Event by event

29 heavy snow. Local standard time, as filed.

Heavy Snow, Snowy Range

When: May 11, 11:00 AM MST to May 12, 12:40 PM MST
Where: Snowy Range forecast zone
Reported by: SNOTEL
Coordinates: 41.675, -106.327 (the zone’s center; the record gives no point)

An estimated 13.5 inches of snowfall was reported at Brooklyn Lake at 700MST, with a snow water equivalent of 0.90 inches. Elevation of the site is 10,240ft.

Heavy Snow, Snowy Range

When: May 11, 11:00 AM MST to May 12, 12:40 PM MST
Where: Snowy Range forecast zone
Reported by: SNOTEL
Coordinates: 41.675, -106.327 (the zone’s center; the record gives no point)

An estimated 15.6 inches of snowfall was reported at Cinnabar Park at 700MST, with a snow water equivalent of 1.30 inches. Elevation of the site is 9,574ft.

Heavy Snow, North Laramie Range

When: May 11, 11:00 AM MST to May 12, 12:40 PM MST
Where: North Laramie Range forecast zone
Reported by: Trained Spotter
Coordinates: 42.253, -105.399 (the zone’s center; the record gives no point)

Douglas 24 S reported an estimated snowfall of 12.0 inches at 830MST.

Heavy Snow, Sierra Madre Range

When: May 11, 11:00 AM MST to May 12, 12:40 PM MST
Where: Sierra Madre Range forecast zone
Reported by: Public
Coordinates: 41.695, -106.931 (the zone’s center; the record gives no point)

An estimated 12.0 inches of snowfall was reported at Riverside 10 W at 1025MST.

Heavy Snow, Central Laramie County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie County forecast zone
Reported by: Official NWS Observations
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

Measured 6.0 inches of snowfall at 430MST. Four inches of snowfall occurred since midnight MST.

Heavy Snow, Shirley Basin

When: May 11, 5:00 PM MST to May 12, 12:40 PM MST
Where: Shirley Basin forecast zone
Reported by: COOP Observer
Coordinates: 41.675, -106.327 (the zone’s center; the record gives no point)

The observer from Shirley Basin measured 5.5 inches of snowfall, with 24 hour liquid precipitation of 0.41 inches.

Heavy Snow, Central Laramie Range and Southwest Platte County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie Range and Southwest Platte County forecast zone
Reported by: Trained Spotter
Coordinates: 41.698, -105.127 (the zone’s center; the record gives no point)

Wheatland 1 W reported an estimated 8.0 inches of snowfall at 600MST.

Heavy Snow, South Laramie Range Foothills

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: South Laramie Range Foothills forecast zone
Reported by: Trained Spotter
Coordinates: 41.481, -105.207 (the zone’s center; the record gives no point)

Cheyenne 17 WNW reported a measured snowfall amount of 9.0 inches at 600MST.

Heavy Snow, Central Laramie County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie County forecast zone
Reported by: Trained Spotter
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

Burns 3 NW measured 9.3 inches of snowfall at 600MST, with a nearby CoCoRaHs site measuring 1.36 inches of liquid precipitation.

Heavy Snow, Central Laramie Range and Southwest Platte County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie Range and Southwest Platte County forecast zone
Reported by: Trained Spotter
Coordinates: 41.698, -105.127 (the zone’s center; the record gives no point)

Chugwater 2 NNW measured 8.0 inches of snowfall at 600MST.

Heavy Snow, Central Laramie County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie County forecast zone
Reported by: Trained Spotter
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

Burns 6 WSW measured 7.5 inches of snowfall at 600MST, with a nearby CoCoRaHs site measuring 1.20 inches of liquid precipitation.

Heavy Snow, Central Laramie County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie County forecast zone
Reported by: NWS Employee
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

Cheyenne 2 E measured 9.1 inches of snowfall at 600MST, with a 24 hour liquid precipitation of 0.96 inches.

Heavy Snow, Central Laramie County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie County forecast zone
Reported by: Trained Spotter
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

Cheyenne 18 E measured 10.0 inches of snowfall at 600MST.

Heavy Snow, South Laramie Range Foothills

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: South Laramie Range Foothills forecast zone
Reported by: Trained Spotter
Coordinates: 41.481, -105.207 (the zone’s center; the record gives no point)

Horse Creek 11 SE measured 9.0 inches of snowfall at 600MST.

Heavy Snow, Central Laramie County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie County forecast zone
Reported by: NWS Employee
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

Cheyenne 9 N measured 9.4 inches of snowfall at 600MST.

Heavy Snow, Central Laramie County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie County forecast zone
Reported by: CoCoRaHS
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

Carpenter 11 WNW measured 6.5 inches of snowfall at 600MST, with a 24 hour liquid precipitation of 1.20 inches.

Heavy Snow, South Laramie Range

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: South Laramie Range forecast zone
Reported by: SNOTEL
Coordinates: 41.481, -105.207 (the zone’s center; the record gives no point)

An estimated 14.4 inches of snowfall was reported at Cow Creek at 700MST. Elevation of the site is 8,330ft. The snow water equivalent was 1.20 inches.

Heavy Snow, Central Laramie Range and Southwest Platte County

When: May 11, 5:00 PM MST to May 12, 8:40 AM MST
Where: Central Laramie Range and Southwest Platte County forecast zone
Reported by: Trained Spotter
Coordinates: 41.698, -105.127 (the zone’s center; the record gives no point)

Wheatland 12 S reported an estimated 12.0 inches of snowfall at 800MST.

Heavy Snow, Central Carbon County

When: May 11, 5:00 PM MST to May 12, 12:40 PM MST
Where: Central Carbon County forecast zone
Reported by: COOP Observer
Coordinates: 41.695, -106.931 (the zone’s center; the record gives no point)

Rawlins 1 N measured 6.2 inches of snowfall at 800MST.

Heavy Snow, Niobrara County

When: May 12, 12:18 AM MST to 1:40 PM MST
Where: Niobrara County forecast zone
Reported by: Law Enforcement
Coordinates: 43.057, -104.475 (the zone’s center; the record gives no point)

An estimated 8.0 inches of snowfall was reported in Lusk at 520MST.

Heavy Snow, Goshen County

When: May 12, 12:18 AM MST to 8:40 AM MST
Where: Goshen County forecast zone
Reported by: Trained Spotter
Coordinates: 42.088, -104.353 (the zone’s center; the record gives no point)

La Grange 4 ESE reported a measured snowfall amount of 7.0 inches at 600MST.

Heavy Snow, East Laramie County

When: May 12, 12:18 AM MST to 8:40 AM MST
Where: East Laramie County forecast zone
Reported by: CoCoRaHS
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

Pine Bluffs 9 NW measured 7.4 inches of snowfall at 600MST, with a 24 hour liquid precipitation of 0.87 inches.

Heavy Snow, Goshen County

When: May 12, 12:18 AM MST to 8:40 AM MST
Where: Goshen County forecast zone
Reported by: CoCoRaHS
Coordinates: 42.088, -104.353 (the zone’s center; the record gives no point)

Yoder 6 SSE measured 7.1 inches of snowfall at 600MST, with a 24 hour liquid precipitation of 0.66 inches.

Heavy Snow, Goshen County

When: May 12, 12:18 AM MST to 8:40 AM MST
Where: Goshen County forecast zone
Reported by: CoCoRaHS
Coordinates: 42.088, -104.353 (the zone’s center; the record gives no point)

La Grange 4 ESE measured 7.0 inches of snowfall at 600MST, with a 24 hour liquid precipitation of 0.63 inches.

Heavy Snow, East Platte County

When: May 12, 12:18 AM MST to 8:40 AM MST
Where: East Platte County forecast zone
Reported by: CoCoRaHS
Coordinates: 42.133, -104.966 (the zone’s center; the record gives no point)

Wheatland observer measured 6.2 inches of snowfall at 600MST, with a 24 hour liquid precipitation of 0.83 inches.

Heavy Snow, East Platte County

When: May 12, 12:18 AM MST to 8:40 AM MST
Where: East Platte County forecast zone
Reported by: COOP Observer
Coordinates: 42.133, -104.966 (the zone’s center; the record gives no point)

The observer at Chugwater measured 6.8 inches of snowfall at 630MST, with a 24 hour liquid precipitation of 0.95 inches.

Heavy Snow, East Laramie County

When: May 12, 12:18 AM MST to 8:40 AM MST
Where: East Laramie County forecast zone
Reported by: Trained Spotter
Coordinates: 41.307, -104.690 (the zone’s center; the record gives no point)

A measured snowfall amount of 9.0 inches was reported at Pine Bluffs at 650MST. Many tree limbs were broken and some houses are without power due to broken power poles and downed power lines.

Heavy Snow, Converse County Lower Elevations

When: May 12, 12:18 AM MST to 12:40 PM MST
Where: Converse County Lower Elevations forecast zone
Reported by: Trained Spotter
Coordinates: 42.972, -105.507 (the zone’s center; the record gives no point)

At Douglas 7 E an estimated 8.0 inches of snowfall was reported.

Heavy Snow, Converse County Lower Elevations

When: May 12, 12:18 AM MST to 12:40 PM MST
Where: Converse County Lower Elevations forecast zone
Reported by: Public
Coordinates: 42.972, -105.507 (the zone’s center; the record gives no point)

Douglas 7 W reported an estimated 10.0 inches of snowfall at 830MST.

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 2010 Every state in 2010 This day in weather history Warnings in Wyoming, May 2010

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: 226856, 226857, 226860, 226863, 226833, 226834, 226837, 226840, 226841, 226842, 226843, 226844, 226845, 226846, 226847, 226851, 226855, 226858, 226859, 226836, 226838, 226848, 226849, 226850, 226852, 226853, 226854, 226861, 226862.