Flood watch issued for southern Utah; southwestern US prepares for Hurricane Hilary

SALT LAKE CITY — Portions of central and southern Utah, including popular recreation areas, are under a flash flood watch issued by the National Weather Service ahead of a monsoon surge that will push into the state.

The flood watch goes into effect Friday at noon and lasts throughout the rest of the day. The areas expected to experience flash flooding are heavily used for recreation but flooding is also possible in urban areas.

Flash floods have previously proved deadly in Utah.

FLASH FLOOD POTENTIAL: A strong tap of monsoonal moisture will prime the pump for more heavy thunderstorms today. #utwx ⛈️

Zion N.P. at risk level 4/4, almost guaranteed. pic.twitter.com/SmjL9BB9N4

— Matthew Johnson (@KSL_Matt) August 18, 2023

The following areas are under the flood watch:

• Central mountains
• Sevier Valley
• Bryce Canyon Country
• Capitol Reef National Park and surrounding areas
• Lake Powell / Glen Canyon Recreation area
• Southcentral Utah
• Southern mountains
• Upper Sevier River valleys
• Western Canyonlands
• Lower Washington County
• Southwest Utah
• Zion National Park (flash flood risk at highest level Friday)

Impacts are expected to include heavy rainfall causing flash flooding of slot canyons, normally dry washes, recent burn scars, creeks, streams and other low-lying and flood-prone locations, according to NWS.

“An ongoing monsoon surge combined with a series of weather disturbances crossing the state will bring an increased threat of flash flooding,” NWS said. “You should monitor later forecasts and be alert for possible flood warnings.”

This includes the cities of:

• Alton
• Beaver
• Big Water
• Brian Head
• Bryce Canyon City
• Bullfrog
• Cedar City
• Circleville
• Cove Fort
• Escalante
• Fish Lake
• Hanksville
• Hurricane
• Ivins
• Joes Valley
• Kanab
• Koosharem
• Loa
• Milford
• Panguitch
• Richfield
• Salina
• St. George
• Springdale
• Torrey

“Those living in areas prone to flooding should be prepared to take action should flooding develop,” NWS said.

Cleanup was already underway Friday from flooding in Cedar City and Enoch, which left a mess in homes, on city streets and even in the hospital and jail. The rain came in quickly Thursday afternoon, flooding parking lots and roads and quickly seeping inside homes and buildings.

“It just really let loose and there was lightning, the power went out,” Cedar City resident Carrie Brown explained. “And water just kept flowing over past the drainage, because the drainage couldn’t handle it at all.”

Capitol Reef National Park closed the Fremont River Trail closed from the Scenic Drive to loop B of the Fruita Campground due to damage from Thursday’s flash flooding.

Due to yesterday's flash flood damage, the Fremont River trail is closed until further notice. Please check in with the visitor center for updates on road and trail conditions in the park.
NPS. A.Smithkin pic.twitter.com/Nu8CxgS6E0

— Capitol Reef NPS (@CapitolReefNPS) August 18, 2023

Hurricane Hilary strengths in Pacific

Hurricane Hilary strengthened to a category 4 storm Friday morning. The U.S. National Hurricane Center said a tropical storm watch has been issued for Southern California, the first time it has ever done that.

BREAKING: Southern California has been issued it's first ever Tropical Storm Watch. The first of its kind on the West Coast. #HurricaneHilary

TIMING: Sunday PM – Monday AM
WINDS: 35-45, Gusts to 65 mph
RAIN: 2-4"
SEAS: 7-12 FT pic.twitter.com/DKbmPbnTRJ

— Matthew Johnson (@KSL_Matt) August 18, 2023

According to the Associated Press, Hurricane Hilary was expected to strengthen a bit more before starting to weaken. It nevertheless was expected to still be a hurricane when approaching Mexico’s Baja California peninsula on Saturday night, and a tropical storm when approaching Southern California on Sunday.

“Heavy rainfall in association with Hilary is expected to impact the Southwestern United States through next Wednesday, peaking on Sunday and Monday,” the hurricane center said. It said there was a substantial danger of flash flooding in an area stretching from San Diego to Las Vegas.

“Rainfall amounts of 3 to 6 inches, with isolated amounts of 10 inches, are expected across portions of southern California and southern Nevada, which would lead to significant and rare impacts. Elsewhere across portions of the Western United States, rainfall totals of 1 to 3 inches are expected.”

Heavy rainfall from #Hilary may produce flash floods and landslides over parts of Baja California through the weekend. Rainfall impacts in the SW US are expected to peak this weekend into Monday. Flash, urban, and arroyo flooding has the potential for significant local impacts. pic.twitter.com/qzdw6CijhA

— NHC Eastern Pacific (@NHC_Pacific) August 17, 2023

The NWS office in Salt Lake City said the greatest amount of tropical moisture will move into southwestern Utah by Saturday night. The risk of flash flooding will be elevated through the weekend and into at least the first half of next week.