Hikers and canyon-area residents should watch for flash flooding in Millcreek Canyon through Friday, Aug. 14, as a stronger-than-usual monsoon system pushes into northern Utah.

The National Weather Service forecasts scattered showers and thunderstorms building Wednesday, Aug. 12, and peaking Thursday, Aug. 13, with what ABC4 meteorologist Cedric Haynes called "the day with the greatest chances across Utah" for storms. The NWS seven-day forecast for the Salt Lake City area shows Thursday afternoon thunderstorms with a high of just 76°F, well below the seasonal average.

The Weather Prediction Center flagged a 5% marginal flash flood risk along and south of I-70 on Tuesday, Aug. 11, expanding to most of Utah by Wednesday as the stronger moisture arrives. No watch or warning has been issued specifically for Millcreek Canyon, but the canyon's narrow terrain and dry washes make it vulnerable during heavy afternoon downpours.

Burn scars amplify the danger statewide

The highest-risk areas are Utah's burn scars, particularly the Cottonwood Fire scar in Beaver and Piute counties, where 97,000 acres burned earlier this year. That scar triggered evacuations near Beaver Canyon on Monday, Aug. 10, according to KUTV, after half an inch of rain produced a debris flow wave. The NWS warned that excessive rainfall over the scar would produce debris flows of rock, mud and vegetation.

The danger is real. Gov. Spencer Cox, who declared a statewide emergency July 22 over wildfires and flooding, urged Utahns in a statement carried by KUTV on Aug. 10 to "heed warnings, avoid flooded areas and never underestimate the power of moving water."

Utah's wildfires have scorched more than 505,000 acres in 2026, according to KSL, leaving extensive burn scars vulnerable to monsoon rains.

What Millcreek Canyon users should know

Canyon visitors should avoid narrow drainages and low-lying creek crossings during afternoon storm hours, typically between noon and 6 p.m. If a flash flood warning is issued, move to higher ground immediately.

The upper portion of Millcreek Canyon Road remains closed for the federally funded road improvement project, which began in May 2025 and is expected to continue through fall 2026. As we reported July 22, the canyon faced a similar but less widespread flash flood threat three weeks ago.

Wasatch Front temperatures are expected to drop into the upper 70s and low 80s by Thursday and Friday, with overnight lows falling into the 50s and 60s. Monsoon moisture should begin tapering off late Friday night into Saturday.