Yellowstone National Park, Wyoming
Regional Weather Alerts
| Alert: | Hydrologic Outlook |
| Area(s): | Big Horn, MT; Carbon, MT; Golden Valley, MT; Park, MT; Stillwater, MT; Sweet Grass, MT; Wheatland, MT; Yellowstone, MT; Sheridan, WY |
| Effective: | 2026-05-10 @ 4:45 pm |
| Onset: | 2026-05-10 @ 4:45 pm -> 2026-05-13 @ 6:15 pm |
| Severity: | Unknown |
| Certainty: | Possible |
| Urgency: | Future |
| Issued By: | NWS Billings MT on 2026-05-10 @ 4:45 pm |
| Headline: | Hydrologic Outlook issued May 10 at 3:45PM MDT by NWS Billings MT |
| Description: |
ESFBYZ Warm temperatures reaching 10 to 20 degrees above normal will enhance snowmelt in the mountains this week, resulting in significantly higher flows on area waterways. Flooding is not expected at this time due to marginal remaining snowpack in the middle elevations between 6000 and 8000 feet. Rivers such as the Yellowstone and Clarks Fork of the Yellowstone are forecast to see flows double the current flows by the end of the week. Smaller streams and creeks flowing out of the mountains will experience rises first this week, with larger rivers and streams further downstream seeing increases by the end of the week. Those with interests along foothills waterways should be prepared for higher water levels this week, and move property and livestock away from rivers, streams, and low lying areas. Runoff may fill culverts, ditches, and storm drains causing water to flow over foothills roadways potentially causing damage. Do not drive over flooded roadways, Turn Around Don't Drown. Recreationists in the mountains and foothills should be prepared for changing conditions and use extra caution when near waterways. Flows will be faster, and the water is very cold. Stay tuned to the forecast. Please report any flooding to local law enforcement and have them relay the report to the National Weather Service. |
| Alert: | Lake Wind Advisory |
| Area(s): | Central and Southeast Phillips; Central and Southern Valley; Petroleum; Garfield; McCone |
| Effective: | 2026-05-10 @ 1:27 pm -> 2026-05-11 @ 10:00 pm |
| Onset: | 2026-05-11 @ 10:00 am -> 2026-05-11 @ 4:00 am |
| Severity: | Moderate |
| Certainty: | Likely |
| Urgency: | Expected |
| Issued By: | NWS Glasgow MT on 2026-05-10 @ 1:27 pm |
| Headline: | Lake Wind Advisory issued May 10 at 12:27PM MDT until May 11 at 9:00PM MDT by NWS Glasgow MT |
| Description: |
* WHAT...Northwest winds 20 to 30 mph with gusts up to 45 mph expected. * WHERE...Fort Peck Lake. * WHEN...From 9 AM to 9 PM MDT Monday. * IMPACTS...Strong winds and rough waves on area lakes will create hazardous conditions for small craft. * ADDITIONAL DETAILS...Expect wave heights of 3 to 5 feet in the afternoon. |
| Alert: | Red Flag Warning |
| Area(s): | Fort Peck Reservation and Daniels/Roosevelt/Sheridan Counties; Dawson/McCone/Prairie/Richland/Wibaux Counties; Northern Valley and Northern Phillips Counties; The Little Rockies; The Lower Missouri River Breaks including the Charles M Russell National Wildlife Refuge; Southern Petroleum and Southern Garfield Counties |
| Effective: | 2026-05-10 @ 1:10 pm -> 2026-05-11 @ 9:00 pm |
| Onset: | 2026-05-11 @ 12:00 pm -> 2026-05-11 @ 4:00 am |
| Severity: | Severe |
| Certainty: | Likely |
| Urgency: | Expected |
| Issued By: | NWS Glasgow MT on 2026-05-10 @ 1:10 pm |
| Headline: | Red Flag Warning issued May 10 at 12:10PM MDT until May 11 at 8:00PM MDT by NWS Glasgow MT |
| Description: |
The National Weather Service in Glasgow has issued a Red Flag Warning, which is in effect from 11 AM to 8 PM MDT Monday. The Fire Weather Watch is no longer in effect. * AFFECTED AREA...Northeast Montana. * WIND...Northwest 20 to 30 mph with gusts up to 45 mph. * HUMIDITY...As low as 15 percent. * IMPACTS...Any fires that develop will likely spread rapidly, particularly for grassland areas. Outdoor burning is not recommended. |
| Alert: | Red Flag Warning |
| Area(s): | Northern Rosebud/Northern Treasure Counties; Custer County; Sioux Ranger District Custer National Forest |
| Effective: | 2026-05-10 @ 1:02 pm -> 2026-05-11 @ 10:00 pm |
| Onset: | 2026-05-11 @ 10:00 am -> 2026-05-11 @ 1:15 pm |
| Severity: | Severe |
| Certainty: | Likely |
| Urgency: | Expected |
| Issued By: | NWS Billings MT on 2026-05-10 @ 1:02 pm |
| Headline: | Red Flag Warning issued May 10 at 12:02PM MDT until May 11 at 9:00PM MDT by NWS Billings MT |
| Description: |
The National Weather Service in Billings has issued a Red Flag Warning...which is in effect from 9 AM to 9 PM MDT Monday. * IMPACTS: Low humidities, hot temperatures, strong gusty winds, and wind shift with a cold front could create erratic fire behavior. * AFFECTED AREA: In Southeast MT Fire Zones...130...132. In Southeast MT and Northwest SD Fire Zone...133. The worst conditions exist along and north of Interstate 94 and US Highway 12. * COUNTIES AFFECTED: In Northwest SD...Harding. In Southeast MT...Carter...Custer...Fallon...Rosebud...Treasure. * COLD FRONT: A cold front will shift winds from the south to the northwest during the day Monday. * WIND: Northwest 15 to 25 mph with gusts to 40 mph. * HUMIDITY: As low as 15 percent. * TEMPERATURES: Up to 83 degrees. |