Rain from the outer edges of Tropical Storm Hilary will remain in place over southern Utah through Tuesday, according to the National Weather Service, resulting in widespread showers and thunderstorms — and possible flash flooding.
Moisture from Hilary, which was a major hurricane before downgrading to a tropical storm, dumped massive amounts of rain on Mexico and Southern California starting Sunday. In Utah, the rare storm is expected to combine with a “renewed monsoonal surge” and bring a continued threat of flooding.
A flash flood watch remains in effect until 6 p.m. Monday in the southwestern quarter of Utah, including Zion, Bryce Canyon and Capitol Reef national parks and Glen Canyon National Recreation Area. The areas most likely to see flooding are slot canyons, normally dry washes, areas near recent burn scars and areas with poor drainage.
In St. George, there’s a 30% to 50% chance of rain on Monday, and a 40% to 80% chance on Monday night.
(Mark Eddington | The Salt Lake Tribune) The Virgin River, as seen near the Bloomington neighborhood of St. George, Utah, on Monday, Aug. 21, 2023. Tropical Storm Hilary's outer edges are forecast to sit over southern Utah through Tuesday.
A high wind warning also remains in effect until 9 p.m. Monday in western Utah, with winds of 30 to 40 mph and gusts up to 60 mph expected. Winds are expected to gradually decrease Monday, according to the weather service.
No flooding is expected in the Salt Lake City area, but there’s a possibility of rain in the forecast every day through Friday — 80% on Tuesday, 20% to 40% on Wednesday and Thursday, and a lower chance on Friday.
Although the weather is not expected to cause flight delays or cancellations out of Salt Lake City International Airport, hundreds of flights out of airports in Southern California and Las Vegas — some headed for Utah — were canceled.
On Tuesday, flash flooding is “probable” in areas including Zion, Bryce Canyon and Canyonlands national parks; it’s “possible” in Arches and Capitol Reef national parks, according to the National Weather Service.