The Sand Creek Fire was first reported on Thursday, September 9, in the Sand Creek drainage about 13 miles west of Lander. The fire grew rapidly due to thunderstorm outflow wind and hot, dry conditions on Friday afternoon, September 10, expanding to nearly 750 acres by the morning of Saturday, September 11.
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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 RIW wrote it up.
The Sand Creek Fire was first reported on Thursday, September 9, in the Sand Creek drainage about 13 miles west of Lander. The fire grew rapidly due to thunderstorm outflow wind and hot, dry conditions on Friday afternoon, September 10, expanding to nearly 750 acres by the morning of Saturday, September 11. The fire grew slowly over the next week, eventually encompassing 929 acres as 120 personnel assisted in suppressing the fire. Cooler and wetter weather moved in around Monday, September 20, with full containment achieved by the end of the month. The fire remained over the backcountry and caused no property damage.
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 Sep 9, 9:47 AM MST, 13 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 1047 AM MDT Thu Sep 9 2021 .SHORT TERM...(Today through Friday) Issued at 427 AM MDT Thu Sep 9 2021 Today will be the hottest day of the week for most locations as the high to our south slowly slides east. 700mb temperatures will peak around 16-18C this afternoon, leading to record or near-record highs for many. Along with the heat, as the ridge flattens a bit, stronger mid-level westerly flow is likely to mix down across northwestern Wyoming. This will bring surface winds up and along with the dry airmass will create elevated to critical fire weather conditions this afternoon across much of the northwest. At the same time, a weak disturbance will move through southwestern Montana. This could lead to some late day convection across far northern YNP, but currently expect most if not all of this activity to remain outside of the forecast area. Flow backs to the southwest on Friday as ridging finally begins to give way to an incoming trough. This approaching system will bring slightly cooler temperatures and even some moisture Friday, with the best chance for isolated showers or storms across western Wyoming. As the southwesterly flow increases, gusty winds are expected across most of the area. East of the Divide, well above normal temperatures and dry conditions will continue. Accordingly, elevated to critical fire weather conditions looks probable mainly east of the Divide and have issued fire weather watches for these areas. .LONG TERM...(Friday night through Wednesday) Issued at 427 AM MDT Thu Sep 9 2021 By around 00Z Saturday a low-amplitude trough should be across the Pacific Northwest. This trough is expected to pull into western Montana Friday night, and then east across Montana on Saturday. The associated Pacific cold front will sweep eastward across the forecast area Friday night into Saturday morning. The best chance of isolated to scattered convection will be across the west and northwest through about 06Z Saturday. However an upper jet streak could still enhance convection over the northwest through the night. Models are then showing some lingering convection mainly over the far south on Saturday. A dry, westerly flow is expected Sunday. Elevated to possibly critical fire weather conditions could occur especially along and east of the Divide. 00Z deterministic models have significant differences for Sunday night and Monday. The 00Z GFS and most of the GFS ensemble members have a mainly dry westerly flow, while the 00Z ECMWF has a trough with decent precipitation across the area beginning Sunday night and lasting through the day Monday. The forecast for now is weighted towards the GFS. By Tuesday, a west to northwest flow develops. A weak shortwave in the flow could produce isolated to locally scattered convection especially over the mountains and adjacent foothills especially east of the Divide. Global models show a trough pulling across southern Canada/extreme northern Rockies in the Wednesday and Thursday time frame. The forecast area right now is at the base of this trough. This pattern favors elevated to possibly critical fire weather conditions. && .AVIATION...(For the 18Z TAFS through 18Z Friday) Issued at 1045 AM MDT Thu Sep 9 2021 VFR conditions will occur through the period. A gusty wind will occur over the northwest and parts of the central through 01Z. Isolated showers and thunderstorms are possible after 23Z in far NW WY through 04Z. Smoke may limit visibility somewhat with a hazy sky, but VFR conditions should prevail. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence forecasts. && .FIRE WEATHER... Issued AT 427 AM MDT Thu Sep 9 2021 Near-record to record highs are expected across most areas today as the strong ridge continues its influence on the region. A continued very dry airmass will keep relative humidity values low. As the ridge flattens a bit, stronger westerly flow is expected to increase surface winds across the northwest this afternoon. Accordingly, critical fire weather conditions are expected across zones 276, 286, 287, 288, and 415. On Friday flow will turn more southwesterly as the ridge begins to break down. This will bring some moisture and cooler temperatures into western Wyoming Friday afternoon, with isolated showers and thunderstorms possible into Friday night. Hot and dry conditions will persist east of the Divide, and with increased winds elevated to critical fire weather conditions are possible across these areas. A cold front will move across the area Friday night, bringing an increased chance of showers across the area and a cooler weekend. && .RIW WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Friday afternoon through Friday evening for WYZ279>283-285-289-300. Red Flag Warning from noon today to 8 PM MDT this evening for WYZ276-286>288-415. && SHORT TERM...Myers LONG TERM...Murrell AVIATION...AR FIRE WEATHER...Myers
Hazardous Weather Outlook National Weather Service Riverton WY 513 AM MDT Thu Sep 9 2021 WYZ001>020-022>030-101200- 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- 513 AM MDT Thu Sep 9 2021 ...Red Flag Warnings and Fire Weather Watches in effect for portions of northwest and central Wyoming today and Friday... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Portions of northwest Wyoming will see elevated to critical fire weather conditions this afternoon and evening. Additionally, near-record to record high temperatures are expected this afternoon. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. Friday...Elevated to possible critical fire weather conditions across much of central Wyoming. Sunday...Elevated to possibly critical fire weather conditions across central and southern areas. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight.
The national radar mosaic for the moment the first event began.
1 wildfire. Local standard time, as filed.
Please see episode for a description.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2021Every state in 2021This day in weather historyWarnings in Wyoming, September 2021
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: 981199.