A moist upper low moved over eastern Utah and resulted significant snowfall over the eastern Uinta Mountains.
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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 GJT wrote it up.
A moist upper low moved over eastern Utah and resulted significant snowfall over the eastern Uinta Mountains.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Sep 24, 2:48 AM MST, 1 hour 12 minutes earlier.
Area Forecast Discussion National Weather Service GRAND JUNCTION CO 348 AM MDT Sun Sep 24 2017 .SHORT TERM...(Today through Monday) Issued at 332 AM MDT Sun Sep 24 2017 A closed upper low will move from central UTah to the northeast today and reach southwest Wyoming by about 03z tonight. A large dry slot will spread over most of the area this afternoon with the only exception being northeast Utah. This area will be close to the low center and receive persistent though decreasing precipitation until about 12z Monday. Monday will be dry and cool. Snowlevels in the wake of trough passage will remain near 9000 feet. .LONG TERM...(Monday night through Saturday) Issued at 332 AM MDT Sun Sep 24 2017 The change of seasons is always a fun time to try and decipher the models as you get farther out in time. No exception today though the models do seem in fairly good agreement out through the upcoming week with respect to the large scale pattern. The large block that has been in place keeping this trough anchored over the Inter- Mountain West will let up and allow the pattern to become a more progressive in the higher latitudes. It is there where the ensemble relative measure of predictability strongly supports an amplified ridge setting up across the northern 2/3 of NOAM by late in the week. The problem area is down here where all the weather will be taking place. This is because an area of low pressure well be left behind by the departing trough early in the week. This low will be cutoff to our southwest as early as Tuesday and become a Rex low as the above mentioned ridge builds to the north of it around the mid to late week period. It is this pattern that is makes things difficult for models to get a handle on. The Cliff Notes are that this low lingers in our vicinity much of the week into next weekend and will keep things unsettled...somewhere. The tap to cold air is not present so snow levels should retreat upward and temperatures look to slowly moderate through the week. Will watch models trends and be ready to expect the unexpected. && .AVIATION...(For the 12Z TAFS through 12Z Monday morning) Issued at 332 AM MDT Sun Sep 24 2017 Areas of low clouds and fog will produce local IFR conditions in the lower elevations of southwest CO with KDRO TAF affected until about 17z. Then conditions will improve and become drier. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...CC LONG TERM...15 AVIATION...CC
Hazardous Weather Outlook National Weather Service GRAND JUNCTION CO 328 AM MDT Sun Sep 24 2017 COZ001>014-017>023-UTZ022>025-027>029-250930- Lower Yampa River Basin-Central Yampa River Basin- Roan and Tavaputs Plateaus-Elkhead and Park Mountains- Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor- Central Colorado River Basin-Grand and Battlement Mesas- Gore and Elk Mountains/Central Mountain Valleys- Central Gunnison and Uncompahgre River Basin- West Elk and Sawatch Mountains-Flat Tops- Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide- Northwest San Juan Mountains-Southwest San Juan Mountains- Paradox Valley/Lower Dolores River- Four Corners/Upper Dolores River-Animas River Basin- San Juan River Basin-Southeast Utah-Eastern Uinta Mountains- Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat- La Sal and Abajo Mountains-Canyonlands/Natural Bridges- 328 AM MDT Sun Sep 24 2017 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight As a strong Great Basin storm moves north over Utah, scattered to numerous showers and isolated afternoon thunderstorms will be focused over northeast UT and move out of western CO. .DAYS TWO THROUGH SEVEN...Monday through Saturday Dry conditions are expected Monday and Tuesday then a storm over the southwestern U.S. will bring an increasing chance of precipitation to much of the area Wednesday through Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1139 PM MDT SAT SEP 23 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1127 PM HAIL 3 W MACK 39.23N 108.92W
09/23/2017 E0.50 INCH MESA CO TRAINED SPOTTER
&&
GJTPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
100 AM MDT SUN SEP 24 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0900 PM HEAVY RAIN 5 WNW TELLURIDE 37.95N 107.90W
09/23/2017 M0.91 INCH SAN MIGUEL CO TRAINED SPOTTER
THE DURATION OF THE HEAVY RAIN EVENT WAS 12
HOURS.
&&
SNSThe national radar mosaic for the moment the first event began.
1 avalanche. Local standard time, as filed.
Snowfall totals of 3 to 6 inches were measured across the area. A locally higher amount of 11 inches was measured at the Mosby Mountain SNOTEL site.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2017Every state in 2017This day in weather historyWarnings in Utah, September 2017
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: 717960.