Utah's active monsoon pattern is expected to bring another round of afternoon and evening thunderstorms Sunday, prompting flash flood concerns in southern Utah. While much of northern Utah may stay dry today, dangerous heat is expected to build across northern and western parts of the state ahead of Monday.
A Flash Flood Watch remains in effect from Sunday afternoon through Sunday evening for much of southwest and south-central Utah. This includes Zion National Park, Bryce Canyon Country, the Southern Mountains, and Lower Washington County. The National Weather Service warned that excessive rainfall could cause rapid flooding of rivers, creeks, streams, and other low-lying areas.
Zion National Park has closed the Narrows and all slot canyons due to the threat of storms and flash flooding. Forecasters noted that flash flooding can develop quickly near slot canyons, dry washes, steep terrain, and burn scars, specifically mentioning Cottonwood, Forsyth, and Monroe Canyon.
A statewide hydrologic outlook also warns that recent burn scars remain especially susceptible to flash flooding and debris flows. In the strongest storms, rainfall rates of 1 to 2 inches per hour are possible. Because burned landscapes often cannot absorb heavy rain, saturated ground from recent rainfall could increase runoff and make debris flows more likely.
Parts of northern and northwest Utah are expected to face dangerous heat on Monday. A Heat Advisory is in effect from noon through midnight Monday for the Salt Lake Valley, Northern Wasatch Front, eastern Box Elder County, Tooele, Rush valleys, and the Great Salt Lake Desert.
Afternoon temperatures are expected to climb above 100 degrees, with overnight lows remaining in the upper 60s and 70s. This heat advisory arrives as firefighters continue to respond to new wildfire starts across northern Utah.
