SAN FRANCISCO >> Northern California residents are bracing for a powerful storm that could be the biggest in five years and prompted the National Weather Service to issue a high wind and flash flood warning.

The storm is expected to arrive Wednesday and pelt the region through Thursday. It could overwhelm waterways and roadway drainage systems, possibly leading to flash flooding.

This storm is “expected to be one of the strongest storms in terms of wind and rain intensity” since storms in October 2009 and January 2008, respectively, said the National Weather Service in Monterey.

Heavy rainfall is expected, especially in the North Bay.

Overall, the heaviest rainfall totals are expected from western Washington to Northern California, with numerous 3- to 5-inch rainfall totals expected. This includes much of the San Francisco Bay Area and Sacramento, the weather service reports.

Mark Ghilarducci, the director of the California Governor’s Office of Emergency Services, issued a warning that the storm will present a risk of flash flooding and debris slides.

“This year was also a significant fire season for Northern and Southern California and burned areas are especially at risk for debris slides. Even regions that don’t experience regular seasonal flooding could see flash flooding during this intense storm system, which could be the largest to date of this year’s rainy season,” he said in a statement.

High winds from 20 to 40 mph are expected, with gusts of 40 to 60 mph.

Authorities are warning motorists to avoid driving through standing water; stay clear of outside roadway lanes, especially at night; keep headlights on at all times; and drive slowly to prevent hydroplaning. People should also have emergency contacts available and a stock a small emergency kit that can sustain each person for three days.

Farther north, a series of strong weather fronts with high winds and heavy rains could lead to flooding and landslides this week in western Washington state.

The National Weather Service expects as much as 14 inches of rain between Monday and Thursday in the Olympic Mountains west of Seattle. And it expects as much as 13 inches of rain in the North Cascades east of the city.

Saturated soils will bring the risk of mudslides, while winds could topple trees.