Hurricane Hilary grew to a Category 4 storm Friday, putting parts of southern California under a tropical storm watch for the first time ever.

And as it moves across the Southwest, parts of California and Nevada could see multiple years’ worth of rain in a matter of days.

It’s still too early to tell exactly what impact the storm will have on Utah — but heavy rain and thunderstorms are likely across the state this weekend.

“For Utah, our biggest impacts are going to be the tremendous amount of moisture that’s moving north into the desert Southwest ahead of that hurricane,” said Christine Kruse, Salt Lake lead meteorologist for the National Weather Service.

Heavy rain from Hilary could bring widespread flooding to Mexico’s Baja California state starting Friday and continuing into Sunday. The National Weather Service is expecting hurricane force winds in the area, which could impact much of southern California as well, spreading north during the weekend.

Utah is currently in a monsoon surge, mostly impacting southern parts of the state — Utah’s desert canyons, washes, national parks and other high risk areas could see flooding through Friday. That monsoon surge will transition into moisture from Hurricane Hilary on Saturday.

By Saturday evening, much of Utah will begin to see heavy rain — residents living east of the Wasatch Mountains along the western part of the state will see the most perception, Kruse said. The rain could persist until Tuesday, with thunderstorms.

If the moisture moves further into central and eastern Utah, that will likely result in unusually intense rain. It’s too early to tell what to expect, but Kruse said parts of Nevada and California could have a whopping two years worth of precipitation in one week.

“We’re talking about some pretty historic flooding potential there,” Kruse said.

She said it’s a low probability for that to happen in Utah, “but it’s something that we’re monitoring because it’s within the realm of possibility.” By Saturday afternoon, meteorologists should have a clear picture of what to expect in the Beehive State.

That means stay away from small streams, slot canyons, burned forests, normally dry washes and other places prone to flooding. The risk is heightened for places like Cedar City, which experienced heavy flooding on Thursday evening. Follow alerts from the Salt Lake National Weather Service office to stay updated.

And if your street does flood, remember the saying “turn around, don’t drown.” It only takes six inches of water to move a car — a foot of water can push a car into the wash, a potentially fatal situation that could require a rescue.