A Flood Watch has been issued for much of southern Utah for Sunday, Oct. 25, as an atmospheric river interacting with a strong cold front brings widespread rain and a heightened threat of flash flooding. The weather system is expected to produce significant rainfall through Monday, with some areas potentially seeing 1 to 3 inches of rain.
Flash Flood Risks and Precipitation
The National Weather Service Salt Lake City issued a Flood Watch for Sunday across much of southern Utah, noting that widespread precipitation is expected to develop late Saturday night. Heavy rainfall may result in flash flooding in areas that are normally dry, such as washes and slickrock areas.
Atmospheric River Impact
The weather pattern is driven by an atmospheric river that is expected to take a southern track through Baja California and propagate through the Desert Southwest. This moisture surge, combined with a cold front, will bring widespread valley rain and mountain snow to Utah and southwest Wyoming through Sunday and Monday.
Saturated Soil Concerns
In southeast Utah and southwest Colorado, the potential for heavy rain is high, with forecasts suggesting 1 to 3 inches of rainfall between Sunday and Monday. The National Weather Service Grand Junction noted that flooding concerns are increasing because soils may already be saturated from previous rainfall and flooding.
Debris and Runoff Risks
The National Weather Service Salt Lake City reported that the system could cause runoff around steep terrain, potentially producing rock, mud, and debris flows onto roadways. There is also a growing concern for flash flood-prone areas including burn scars, washes, slot canyons, and arroyos.
Regional Flash Flood Ratings
The National Weather Service's flash flood potential rating for Sunday indicates several areas face significant risks. In southern Utah, Zion National Park is listed as having a probable risk of flash flooding, while Bryce Canyon National Park is also rated as probable. Snow Canyon / Red Cliffs and Grand Staircase-Escalante West are also listed as probable for flash flooding. Other areas, such as Arches National Park and Canyonlands National Park, are not expected to experience flash flooding on Sunday.
Mountain Weather and Travel
The weather system will also impact mountain elevations. A cold front pushing from northwest to southeast Sunday night into Monday is expected to drop snow levels to around 8,000 feet by Monday morning, and potentially as low as 7,000 feet by Monday evening. Travelers should be aware that slippery stretches are likely over mountain passes as the colder air moves in.
Forecast Outlook
Following the heavy precipitation, weather conditions are expected to clear. Forecasts indicate that precipitation will taper off Monday evening, leading to cooler and drier conditions starting Tuesday.
