Strong downslope winds developed in the vicinity of Clark and produced locally high winds. At the weather station 8 miles SSW of Clark, there were several wind gusts over 58 mph, including a maximum of 71 mph.
Every event with a place to put it; 1 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.
Strong downslope winds developed in the vicinity of Clark and produced locally high winds. At the weather station 8 miles SSW of Clark, there were several wind gusts over 58 mph, including a maximum of 71 mph.
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 Jan 17, 12:39 PM MST, 5 hours 36 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 1239 PM MST Wed Jan 17 2018 .SHORT TERM...This afternoon through Saturday High cirrus and dry conditions will continue this afternoon into tonight. Basins and valleys will remain trapped under inversions, keeping temperatures at or below freezing this afternoon. Winds will begin to increase over the Cody Foothills and Absarokas and the Wind Corridor, from the Green Mountains to Natrona County tonight into Thursday, as the flow aloft turns more SW. This will continue Thursday night into Friday, as a cold front begins to slowly make its way through the forecast area. Have kept winds just below warning criteria for now, but there could be isolated (favored) areas that gust over 60 mph during the day Friday, such as Outer Drive on the south side of Casper. The moist, SW flow will bring steady precipitation to NW portions Thursday night into Friday. Most of this will occur over Yellowstone, as the best jet dynamics and vicinity of the cold front will be located over this area. Otherwise, expect only advisory amounts (6-9 inches) of snow for the higher elevations. Jackson Valley could receive 2 to 4 inches and Star Valley 1 to 2 inches. As the front progresses southward Friday evening, snowfall east of the Divide seems unlikely at this point. However, snow across western portions will spread over southern Lincoln County and into Sweetwater and Natrona counties. The upper low responsible for this will be well to the south, over the Four Corners and eject out over E CO. The best chances for snow from Casper to E Sweetwater County will be due to the deformation band from this system. If this system progresses any further east or south, this will limit snow amounts in these areas. For now, it looks like a slam dunk for major impacts for CYS's area. Either way, snow will gradually subside from NW to SE during the day Saturday. .LONG TERM...Saturday night through Wednesday night The splitting storm system that will eject off the main closed low that is now spinning off the Pacific coast, due west of the Canadian/US border, will have the bulk of the energy well to the south over the Desert Southwest, with the trough axis over us by Saturday night. The ECMWF and the Canadian are still a little slower than the GFS in swinging the axis through. Will still go with the idea that the first few hours of the evening on Saturday will feature mainly upslope snowfall enhanced by sfc ne winds circulating around the Eastern Co sfc low after sfc frontogenesis takes place over our CWA. We can expect about another inch or so of snow in the upslope favored areas from Lander to Casper as well as down in Sweetwater County. Then the sfc flow quickly becomes anticyclonic before 06z Sunday. Behind this exiting weather system, temperatures will be around 10 to 15 degrees colder along with a precip free day Sunday. After the short break in the action, our attention then shifts to the next weather feature tracking east southeast across the Pacific Northwest Sunday night and the Northern Rockies Monday. Snowfall will break out over the far west during the night Sunday night and will continue through Monday. The GFS depicts this feature the most distinctly. The isentropic lift in the far west, ahead of this system, is not depicted with the latest model run as it has been in previous runs. Then after this feature quickly exits the region, the upslope flow will continue to stream off the Pacific as the flow backs and becomes more difluent by Wednesday night ahead of the next Pacific trough. The result will be periods of light snow across the far west Monday night through Wednesday, with snow increasing once again over the far on Wednesday night. After temperatures become colder by Sunday morning, temperatures will remain fairly steady through the middle of next week. Areas east of the divide will remain dry Sunday through Wednesday night. && .AVIATION...For the 00Z TAFS through 00Z Friday West of the Continental Divide...KJAC, KBPI, KPNA and KRKS Increasing southwest flow aloft and high clouds will occur for the rest of this afternoon. Clouds will lower and thicken after 12Z Thursday, as the next Pacific weather system approaches the area, during which time areas of MVFR conditions and mtn obscurations will be found in the far western portion of Wyoming. East of the Continental Divide...KCPR, KCOD, KRIW, KLND, and KWRL VFR conditions will prevail through the period. Surface southwest winds 15-25 knots will prevail through the wind corridor through 06z Thursday, vicinity 50SM NE KRKS-KCPR. These winds will increase 06z- 21z Thursday. && .FIRE WEATHER... Mainly dry weather will continue through Thursday. Inversions will continue over the Basins east of the divide, although shallower than in recent days. Mixing and smoke dispersal will be generally poor. A gusty breeze will continue across the southwestern wind corridor from the Red Desert through Natrona County. These winds will continue tonight into Thursday and Friday. Strong winds will also develop over the Absarokas and portions of the Cody Foothills Thursday into Friday. Snow will return to NW portions (especially Yellowstone) Thursday night into Friday. Snow will then spread to the south Friday night into Saturday, with the focus from southern Lincoln and Sweetwater counties over to Natrona. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...LaVoie LONG TERM...Lipson AVIATION...Lipson FIRE WEATHER...LaVoie
Hazardous Weather Outlook National Weather Service Riverton WY 134 AM MST Wed Jan 17 2018 WYZ001>020-022>030-181200- 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- 134 AM MST Wed Jan 17 2018 This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Thursday into Thursday night, Strong to possibly high winds are expected in the Absaroka Mountains and in the Northern Cody Foothills. Thursday night into Friday morning, strong to possibly high winds between Jeffrey City and Casper. Late Thursday Night through Saturday, A strong storm system will impact the west with snow and wind Thursday night and Friday. There is a good chance of snow spreading into central and south- central Wyoming Friday night and Saturday. Snow is then expected to end Saturday night. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight. Team Riverton
Special Weather Statement National Weather Service Riverton WY 1252 PM MST Wed Jan 17 2018 WYZ003-181100- Cody Foothills- Including the cities of Cody and Meeteetse 1252 PM MST Wed Jan 17 2018 ...Strong winds may return to the Cody Foothills Thursday and Thursday night... Strong winds may develop across the Cody Foothills Thursday into Thursday night. Travelers along highway 120 from just south of Cody through the Clark area may experience strong cross winds during this time. Expect west winds to increase to 25 to 35 mph with gusts 45 to 55 mph and possibly higher in the normally windy spots. Stay tuned for further updates on this potential wind situation. WYZ019-020-181100- Green Mountains and Rattlesnake Range- Natrona County Lower Elevations- Including the cities of Jeffrey City and Casper 1252 PM MST Wed Jan 17 2018 ...Strong winds may return to the Wind Corridor Thursday night and Friday... Strong winds may develop from South Pass over to Muddy Gap and Casper Thursday night into Friday. Travelers along Highway 28, 220 and 789 may experience strong winds during this time. Strong cross winds may also occur on Outer Drive on the south side of Casper. Expect west to southwest winds to increase to 25 to 35 mph with gusts 45 to 55 mph and possibly higher in the normally windy spots. Stay tuned for further updates on this potential wind situation. Team Riverton
Special Weather Statement National Weather Service Riverton WY 112 PM MST Wed Jan 17 2018 WYZ001-002-012-013-181100- Yellowstone National Park-Absaroka Mountains- Teton and Gros Ventre Mountains-Jackson Hole- Including the cities of Lake, Mammoth, Old Faithful, and Jackson 112 PM MST Wed Jan 17 2018 ...Another dose of snow returning Thursday and Friday... Moist southwest flow will stream over northwest portions Thursday afternoon, as a cold front approaches Yellowstone from southwest Montana. Light snow showers will be possible from Jackson northward into Yellowstone Thursday afternoon, with the best chances occurring over southwest Yellowstone. This will continue into the evening hours, with moderate to heavy snow possible over the park after midnight. Light to moderate snow will also be possible over the Tetons by this time. Light to moderate snow will then spread southward during the morning hours Friday and encompass the western mountains and valleys through the afternoon. 7 to 10 inches, with localized amounts up to 1 foot, are expected across Yellowstone. 6 to 9 inches are expected in the Tetons and Absarokas, with 3 to 5 inches in Jackson Valley and 1 to 2 inches in Star Valley.
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
The weather station 8 miles SSW of Clark had several wind gusts over 58 mph, including a maximum of 71 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2018Every state in 2018This day in weather historyWarnings in Wyoming, January 2018
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: 729001.