The National Weather Service in Boise issued a severe thunderstorm warning Thursday afternoon for central Canyon County and surrounding areas in southwestern Idaho and southeastern Oregon, alerting residents to prepare for dangerous weather conditions including large hail and heavy rainfall.
The initial warning, issued at 5:27 p.m. MDT on July 23, 2026, covered central Canyon County and northwestern Owyhee County in Idaho, as well as east-central Malheur County in Oregon. The storm posed a significant threat to the Treasure Valley region, with forecasters warning of quarter-size hail capable of causing vehicle damage and torrential rainfall that could trigger flash flooding.
Storm Path and Timing Across Canyon County
When the warning was issued, the storm was located near Succor Creek Campground, approximately 20 miles south of Parma, moving northeast at 30 mph. Weather officials projected the system would reach populated areas across Canyon County within minutes of the initial alert. The storm was expected near Homedale around 5:40 p.m. MDT, followed by Greenleaf and Huston around 5:50 p.m. MDT, and Caldwell and Sand Hollow around 6 p.m. MDT.
As the storm continued to move and intensify, the National Weather Service issued an updated severe thunderstorm warning extending over northeastern Ada County, with the system accelerating northward at 45 mph. The extended warning remained in effect until 9:30 p.m. Thursday, reflecting the storm’s continued movement across the region.
Hazard Warnings and Flash Flood Threat
In addition to the thunderstorm warning, forecasters issued a flash flood warning for northeastern Ada County until 12:30 p.m. Friday as the system moved through the area. Radar indicated the storm was capable of producing quarter-size hail, with meteorologists warning that heavy rainfall accompanying the system could lead to localized flash flooding in low-lying and drainage areas.
The combination of large hail and torrential rainfall posed dual threats to residents and property across the warning area. Vehicle owners in the affected regions were advised to seek shelter and move vehicles under cover if possible, while residents in flood-prone areas were urged to remain alert for rising water conditions.
Impact on Canyon County Residents
Residents throughout Canyon County, particularly those in Caldwell, Homedale, Greenleaf, and surrounding communities, faced the brunt of the severe weather threat. The rapid movement of the storm system and the intensity of the associated hazards meant that those in the affected areas had limited time to prepare once the warning was issued.
Families and businesses in the region were advised to secure outdoor items, avoid unnecessary travel during the storm’s passage, and remain indoors away from windows during the heaviest rainfall and hail activity. Motorists on Interstate 84 and other highways crossing the affected area were cautioned to reduce speed and exercise extreme caution during the storm’s approach.
Weather Preparedness Reminder
The issuance of the severe thunderstorm and flash flood warnings underscores the importance of staying informed about rapidly changing weather conditions during severe weather season. The National Weather Service recommends that Canyon County residents monitor local weather alerts, sign up for emergency notifications through their county or city, and maintain awareness of evacuation routes in flood-prone areas.
Canyon County typically experiences severe thunderstorms during late spring and summer months, with hail and flash flooding posing recurring hazards to the region. Residents are encouraged to develop household emergency plans and maintain supplies of drinking water, first aid kits, and battery-powered radios for use during severe weather events.
What Comes Next
As severe weather season continues through the summer months, Canyon County residents should remain vigilant about weather forecasts and warnings issued by the National Weather Service. Those living in flood-prone areas near streams, creeks, and drainage systems should be especially attentive to flash flood warnings. For additional information on weather preparedness and emergency response, residents can contact their local Canyon County Emergency Management office or visit the National Weather Service Boise office website for current forecasts and warnings affecting the Treasure Valley region.