Ample Pacific moisture and a cold front moved into the Tetons and brought very heavy snow to some locations. At the top of the Jackson Hole Ski resort, 26 inches of new snow fell.
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.
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.
Ample Pacific moisture and a cold front moved into the Tetons and brought very heavy snow to some locations. At the top of the Jackson Hole Ski resort, 26 inches of new snow fell. Many other locations around the Tetons reported anywhere from 11 inches to 20 inches.
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 Nov 10, 3:05 AM MST, 6 hours 55 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 305 AM MST Tue Nov 10 2020 .SHORT TERM...(Today through Wednesday) Issued at 215 AM MST Tue Nov 10 2020 Flurries/very light snow has already begun over the far west this morning. The intensity looks to remain relatively light most of the day as a transitory ridge pulls across the region. Decent isentropic upglide will develop tonight as the flow becomes more westerly. Along with this, models are showing a weak disturbance in conjunction with dynamics from a left-exit region of an upper jet enhancing snowfall rates late tonight into Wednesday morning. This system will continue to push east into Plains with some residual energy pulling back across the area late Wednesday into the long term. A weak cold front is expected to push south into N. Wyoming Wednesday afternoon which could bring some light snow in that area. Until then the main issue for areas east of the Divide will be some gusty winds in the Cody Foothills as well as from South Pass to Casper. No changes were made to the ongoing winter weather advisory over far western Wyoming. Could see some warning amounts even in the lower elevations, but the snow is over a long enough period where the advisory will be sufficient to deal with the associated impacts. .LONG TERM...(Wednesday night through Monday) Issued at 215 AM MST Tue Nov 10 2020 Overview...Snow is expected to continue across the western mountains but will slowly drift eastward toward the Winds and Wind River Basin. Trough departs quickly but northwest flow keeps snow showers in the northwest. Brief break in the precipitation as ridging builds in late Thursday into Friday. Southwest flow could bring increased winds to the Wind Corridor. Another upper-level trough brings more snow to the western mountains while east of the Divide remains dry. Northwest flow keeps the potential for snow in the western mountains but model agreement brings upper-level ridging to dry out the area early next week. Synopsis...The broad trough that has been sitting across the area producing the showers in the west will slowly start to drift eastward. Snow could be expected to move with it bringing the potential for snow to East of the Divide locations. That has been reflected in the grids with increased chances mainly in the western Wind River Basin, the Bighorns and Bighorn Basin. Also kept PoP in the south. Shoshoni and eastward should stay mainly dry. Winds through the Wind Corridor however will be the big concern ahead of the cold front through Thursday. Winds begin to diminish after trough departure and temperatures begin to climb across the area. Upper-level ridging will keep the area dry into late Friday; however, the next trough for the weekend brings increased chances of precip across the west as early as Saturday morning. This appears to be a mainly West of the Divide event as moisture is lacking across the valleys. Winds will pick up again across the south and through the Wind Corridor. With the upper-level support these winds could be stronger compared to Thursday. As the trough ejects southeastward; northwest flow will keep snow showers in the northwest. These showers will gradually diminish as model agreement points toward upper-level ridging across the area as height rises slowly move in Monday. Ridging looks to remain in place through Wednesday. Depending on the strength of the ridge some daily high temperature records could be broken. Southwest flow to end the period looks to be indicative of a Pacific trough but it is well too early to discuss that potential. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 215 AM MST Tue Nov 10 2020 West of the Continental Divide...KBPI/KJAC/KPNA/KRKS Terminals Expect VFR conditions through the TAF period except for KJAC. Low clouds, with MVFR ceilings will continue near KJAC through the period. Snow activity will increase at KJAC by 17Z, before gradually decreasing by 03Z Wednesday. A band of snow will impact KPNA/KBPI and KRKS between 03Z and 10Z Wednesday with MVFR conditions. Gusty winds will continue at KRKS, until the band of snow moves past. Winds will be a bit gusty at the other terminals this afternoon and early evening. East of the Continental Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals Skies have primarily cleared out, with a band of cirrus exiting eastward. Expect VFR conditions through the TAF period. Gusty winds will return at KCPR by 15Z and continue through 01Z. Light winds expected at the other terminals through the period. High clouds will spread over the area early Tuesday afternoon, clearing out again by early evening. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued AT 215 AM MST Tue Nov 10 2020 West of the Divide, expect increasing snow today with significant snow tonight and Wednesday. East of the Divide, enough wind and deep enough mixing will result in good to very good smoke dispersal across much of the area this afternoon except in central portions of basins which will have poor to fair smoke dispersal. Otherwise dry and cool today. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 2 PM this afternoon to 10 PM MST Wednesday for WYZ013-023. Winter Weather Advisory from 11 AM this morning to 10 PM MST Wednesday for WYZ001-012. && SHORT TERM...Murrell LONG TERM...Vorst AVIATION...LaVoie FIRE WEATHER...Murrell
Hazardous Weather Outlook National Weather Service Riverton WY 317 AM MST Tue Nov 10 2020 WYZ001>020-022>030-111315- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Big Horn Basin-Southwest Big Horn Basin- Southeast Big Horn Basin-Owl Creek and Bridger Mountains- Bighorn Mountains West-Bighorn Mountains Southeast- Northeast Johnson County-Southeast Johnson County- Teton and Gros Ventre Mountains-Jackson Hole- Wind River Mountains West-Wind River Mountains East- Upper Wind River Basin-Wind River Basin-Lander Foothills- Green Mountains and Rattlesnake Range- Natrona County Lower Elevations-Casper Mountain-Star Valley- Salt River and Wyoming Ranges-Upper Green River Basin Foothills- Upper Green River Basin-South Lincoln County- Rock Springs and Green River-Flaming Gorge-East Sweetwater County- 317 AM MST Tue Nov 10 2020 ...Winter Weather Advisory for portions of far west Wyoming Today through Wednesday Night... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Significant snow over the far west, especially tonight into Wednesday morning. Please see the winter weather advisory for more information. Windy west to southwest winds from Rock Springs to Casper. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Wednesday...Significant snow continues over the far west. Friday night and Saturday...A chance of snow in the west. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
2 winter storm, 1 heavy snow. Local standard time, as filed.
Heavy snow amounts in the Teton and Gros Ventre mountains ranged from 11 to 20 inches of snow.
Heavy snow occurred, with 26 inches of snow reported at the Jackson Hole Ski resort.
Snow Squall. It was estimated that an inch of snow occurred with the snow squall and visibility dropped to under a half of a mile with the passing snow shower. Webcams also showed very poor visibility on Interstate 80.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2020Every state in 2020This day in weather historyWarnings in Wyoming, November 2020
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: 923863, 930429, 930443.