St. George's dry spell ends at 78 days; flash flood risk picks up as monsoons return

SALT LAKE CITY — One of Utah's longest active dry spells has finally come to an end after more than two months as monsoon moisture returned to Utah this week.

St. George received 0.05 inches of rain on Tuesday, snapping a 78-day stretch without any measurable precipitation dating back to April 28.

"It's a good thing we saw that rain," said KSL meteorologist Matt Johnson, adding that the city's longest streak remains over 150 days back in 2019.

However, as welcomed monsoonal summer storms return, the National Weather Service says the risk of flash flooding — especially near Utah's outdoor gems — is also going up.

The potential flooding is tied to a high-pressure system currently set up south of the Four Corners region. It's gradually moving west, helping set up the convective pattern needed to produce the scattered showers during the monsoon season.

Weather service meteorologists say the activity will peak on Thursday, opening up storm potential across the state. That's when Salt Lake City's dry spell could potentially end after it last received rain on June 21.

"Almost everybody has a chance to see something fall from the sky," Johnson said. "It looks like a pretty good setup."

The downside is that it will also bring "significant flash flood threat" across a large chunk of southern and south-central Utah, according to weather service. The agency warns that flash floods are "probable" at recreation gems like Lake Powell, Zion National Park, San Rafael Swell and Grand Staircase-Escalante National Monument. Flooding is also "possible" at other major parks in those regions.

The storm potential will last at least another day. The risk of flash flooding at Bryce Canyon National Park and Natural Bridges National Monument is elevated to probable on Friday while it's downgraded to possible at Lake Powell, Zion National Park and the San Rafael Swell, according to the weather service.

Johnson said monsoonal storm dynamics are expected to remain in place for the next five to seven days, which could produce more scattered showers into next week.

Any moisture could improve the drying conditions that have helped fuel new wildfires in recent weeks, especially in southwest Utah. The Silver King and Deer Springs fires, combined, have burned nearly 30,000 acres of land in Piute and Kane counties, respectively.

There are other benefits to the current pattern. Johnson points out that the winds from the south should push wildfire smoke that has moved into Utah north into Canada, improving air quality.

Hot conditions are still expected to persist with the storms still in place. High temperatures are currently forecast to remain at or near 100 degrees over the next week along the Wasatch Front, including on Pioneer Day. Highs will remain between 105 to 110 degrees near St. George during that time.

Full seven-day forecasts for areas across Utah can be found online, at the KSL Weather Center.

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