LOS ANGELES >> One person died and two others were missing in a raging stream channel as a powerful storm pounded California with rain and snow Tuesday, raising fears of flash flooding and concerns that the weather could keep people from Election Day voting.

The current in a canal in Ontario, a city in Southern California, swept six people away, killing one, the Ontario Fire Department said.

Firefighters were able to pull three others from the water, and they have been hospitalized. Crews continued searching for those missing amid the downpour, the department said.

Some of the heaviest rain is expected later Tuesday in Orange County, which is holding several very close U.S. House races that could determine which party controls Congress.

The Republican Party of Orange County urged members to vote early and avoid getting stuck in the rain on Election Day.

“Election day lines are long and typically one to two hours long. Don’t risk getting caught waiting in the rain to cast your ballot,” an email sent by the party Monday said.

The storm arrived Monday and is forecast to last into midweek. But it was already causing trouble in some areas Tuesday.

The city of Duarte, in the Southern California foothills of the San Gabriel Mountains, issued mandatory evacuation orders late Monday night for about 25 homes in the Fish Fire burn scar area. Other evacuation orders are in place through Wednesday morning for canyon areas in the Santa Ana Mountains’ Bond Fire burn scar.

In Northern California, meteorologists issued a flash flood watch through 5 p.m. Tuesday, warning that heavy rainfall could lead to debris flows and flash flooding in the burn scars of the Colorado and River wildfires.

Between 1 and 3 inches (2.54 and 7.62 centimeters) of rainfall are expected through Wednesday in the Los Angeles area’s coast and valleys. The foothills and mountains could see up to 5 inches (12.70 centimeters). Thunderstorms are expected to last Tuesday afternoon into the evening, National Weather Service meteorologists said.

Meteorologists say mountain peaks above 6,000 feet (1,800 meters) elevation could get 6 to 12 inches (15 to 30 centimeters) of snowfall, with 20 inches (50 centimeters) possible locally.

The National Weather Service issued a winter storm warning for the greater Lake Tahoe area on Tuesday as heavy snow fell in the region, causing backups in major highways in the area. The agency warned driving in the region would be extremely difficult, if not impossible.

“Be prepared for whiteout conditions and sub-zero wind chills along ridgelines and near the mountain passes,” the agency said in its alert, adding that the hazardous conditions will affect motorists during peak commute times.