UPDATE: A flash flood watch went into effect for parts of Utah Tuesday morning as the remnants of Tropical Depression Rosa are expected to reach the state. The watch means heavy rains and flooding is possible in some areas.

Rosa's edges dropped light rain early Tuesday morning in Phoenix, Arizona.

Rosa, which was downgraded early Tuesday from a tropical storm, already has pounded the Northern Baja and Southern California desert regions, and the Mexican state of Sonora just south of the Arizona border, CNN reported.

SALT LAKE CITY — The remnants of Hurricane Rosa are expected to move up from the Pacific Ocean, Baja Peninsula and Arizona into Utah Monday, prompting flooding concerns.

Rain and thunderstorms from Rosa are expected to reach southern Utah by Monday afternoon and into Monday evening, said KSL meteorologist Grant Weyman. The storm is expected to reach the Wasatch Front by Tuesday morning, with rain expected for most of the day.

It could be a tropical depression by the time it reaches Utah, National Weather Service meteorologist Christine Kruse said in a Facebook video posted by the agency Monday morning.

The forecast calls for areas of Utah to see anywhere from 1/3 inch to 2 inches of rain or more from the storm, Weyman added. He expected mountainous areas and area in southern Utah will see the most amount of rain.

Kruse said it probably won’t produce snow for higher elevation areas because it will be warmer rain.

“We’ll start seeing passing rain showers, storms, some can be heavy at times through a good portion of the state,” Weyman said. “We’ll continue to see some showers into Wednesday, but they’ll be more sporadic, and even Thursday, as well.”

Hurricane remnants reaching Utah, a landlocked state, is rare but not unheard of. National Weather Service officials said a storm like Rosa impacting Utah happens about every five to seven years on average. For example, the remnants of Hurricane Nora hit Utah in 1997, on a path similar to Rosa’s projected path.

“Strong winds, nearing hurricane force, downed many trees across southwestern Utah, at elevations of 10,000 feet and higher,” National Oceanic and Atmospheric Administration’s Weather Prediction Center officials wrote in a history of the storm.

Remnants of Hurricane Bud also reached southern Utah in June.

Risks and benefits

There’s a good possibility of flooding with the rain expected from Rosa. In fact, the majority of the state was placed on a flash flood watch Saturday that will take effect Monday afternoon for parts of southern Utah and Tuesday morning in northern Utah.

The biggest areas of concern center around the various burn scars in the state, especially in southeastern Utah County where three major fires have burned southeast of Spanish Fork since August. Rain could trigger debris flows, which is flash flooding with ash and debris from the fires.

Matt Buddie, flood insurance specialist for Federal Emergency Management Agency Region VIII, told KSL.com in September that people who live near where a wildfire burned should keep tabs with local emergency officials to see if they are at risk.

“If you can look up and see a burn scar, there’s a good chance that you’re at risk for flooding or debris flow,” he said.

Kruse said the flood watch means residents should prepare for the possibility of flooding or if a warning is issued.

“Develop your action plans now,” she said. “Know what you’ll do if you’re in the path of where a debris flow might impact you.”

Some cities began sandbagging over the weekend. That included Woodland Hills and Elk Ridge in Utah County, which was evacuated by the nearby Bald Mountain Fire in September.

“What they’re doing is exactly what you should do,” Weyman said. “We hope it won’t happen, but you have to prepare for it. It’s anybody’s guess where those little pockets of the heaviest rain hit. … You don’t want that to happen in those areas affected by the fires.”

Kathy Holder, state floodplain manager for Utah Emergency Management, said homeowners in those communities in Utah County can enroll in the National Flood Insurance Program without having a 30-day waiting period. More information about that can be found at floodsmart.gov.

In addition to the burn scar areas, Weyman said steep canyons, mountain areas and poor drainage areas are also prone to flash flooding. National Weather Service meteorologist Charlotte Dewey said areas with slick rocks and near urban streams should also prepare for any possible flooding.

However, there are benefits from the rain, too. The National Weather Service tweeted Monday that Salt Lake City recorded only a traceable amount of rain in September, becoming the city’s driest September since 1951. The amount of rain forecasted from the storm is about the same as a months worth of rain to pour in a 36-hour span, Weyman said.

Utah is also in the middle of a statewide drought, with central and eastern portions of the state dealing with the worst of it.

Monday is the start of Utah’s new water year (water years start Oct. 1 and run through Sept. 30 the following calendar year) and the rain anticipated is expected to give Utah a much-needed boost after an extremely dry summer helped worsen the state’s drought situation.

Kruse said there are also three other rain-producing storms expected to hit Utah over the next week.

“We’re starting off our water year on a great note,” Weyman added, “and hope to get more rain to come in the rest of October, November and more mountain snow this season.”

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