By Molly Riel

SACRAMENTO (CBS13) – California is bracing for a wet weekend, with an extreme atmospheric river expected to drench the state beginning Sunday. While many are welcoming the much-needed rain, state and county officials say it comes with risks.

Dr. Michael Anderson, California State Climatologist for the Department of Water Resources, says the anticipated storm is “a mix of being both benefit and hazard.” He says one of the biggest perks we’ll see is in the mountains, where the landscape will get wet before the snow sets in.

READ MORE: Suspect Arrested After Car Chase In Downtown Sacramento

“We saw what the lack of that did this past spring,” he explains, “Dry soils and snowpack that just did not produce runoff.”

Dr. Anderson believes there will be more runoff this year, which will hopefully restore some of the lost storage water.

When it comes to concerns, Dr. Anderson says people mostly need to be aware of rapidly changing circumstances, like rising rivers. He urges residents to check their gutters and make sure water will drain. He also pointed out that trees have been drought-stressed, so keep an eye out if winds develop.

One concern he says people probably shouldn’t lose sleep over is the possibility of contaminated drinking water. The concern stems from recent wildfires.

READ MORE: Wet Weather May Have Played Role In Davis Crash That Killed 1-Year-Old

“Metals from batteries or cars could be mobilized from the rain,” Dr. Anderson explains.

Those pollutants could be swept into the Feather River, which flows into the Oroville Dam, a major water supply for the region. However, Dr. Anderson says the amount of rain we’re expecting should dilute the pollutants to a degree, and whatever is left would likely be treated in each community’s water treatment system.

In preparation for the storm, the Sacramento County Department of Human Assistance (DHA) activated its severe weather sheltering program, offering 100 motel vouchers to highly vulnerable people, which includes the elderly and people with conditions that could be compromised by the rain.

DHA Public Information Officer Janna Haynes says with a houseless population hovering around 5,500, there aren’t nearly enough vouchers for everyone, but she is hoping those who need extra protection will get it.

MORE NEWS: Fantasy Football Start Or Sit Week 13: Elijah Mitchell Looks To Take Advantage Of Seahawks' Defense

“We can’t help everybody every night,” she says, “but we do what we can when we can with the resources we have.”