Gov. Gavin Newsom issued a state of emergency throughout California on Wednesday as a powerful storm slowly made its way across the state, including into the Southland, with potentially heavy downpours again raising fears of flooding and debris flows in recent burn areas.

Light rain fell across most of the area Wednesday morning, making for a wet but tolerable commute. But as the storm moves closer, rain will slowly begin to intensify, beginning with rates of one-tenth to a quarter-inch per hour in some areas, according to the National Weather Service. By Wednesday afternoon and night, however, rain will keep getting heavier, with downpours continuing into Thursday and reaching one inch per hour in some locations. The “peak intensity” of the storm is expected to be Thursday morning.

NWS forecasters said 2 to 4 inches of rain could fall across most of the area, with some mountain areas receiving 4 to 8 inches before the storm moves out.

“These rates and amounts could cause significant flash flooding or debris flows across the region in and outside of recent burn scars with significant small stream and urban flooding possible,” according to the NWS.

Long Beach will face multiple weather advisories due to the storm. According to the NWS, a wind advisory will go into effect in the city at 6 p.m. Wednesday and last through 10 a.m. Thursday. Long Beach will also be under a flood watch starting at 10 p.m. Wednesday, which will last until 4 p.m. Thursday. And lastly, the NWS is forecasting a high surf advisory for Long Beach from 6 a.m. Thursday until 10 a.m. Friday.

According to the governor’s office, Newsom’s declaration will bolster emergency response efforts while authorizing the mobilization of the California National Guard for disaster response. It also directed Caltrans to request immediate assistance from the Federal Highway Administration to expedite road repairs due to the storms.

“This state of emergency will allow the state to respond quickly as the storm develops and support local officials in their ongoing response,” Newsom said in a statement.

According to the governor’s office, state fire and rescue personnel have been pre-positioned across the state to quickly respond to emergencies such as mud and debris flows, flooding and landslides.

The state Health and Human Services Agency was also working with local agencies to assist with efforts to notify vulnerable populations — such as people who are homeless and or who have disabilities — about the pending storm and provide services such as temporary shelter.

State officials urged residents to avoid non-essential travel during the storm and to be prepared for possible power outages by having flashlights and batteries ready. Residents were also urged to have enough non-perishable food available to last for three days if needed in the event of a major emergency.

“There will be many potential problems associated with this storm system including urban and small stream flooding, rocks and debris on roads, downed trees and numerous power outages, and mud and debris flows out of recent burn areas,” according to the NWS.

Conditions are expected to dry out by Thursday night, continuing into Friday. A series of “weak disturbances” are anticipated over the weekend, but “there will likely be drier and less cloudy intervals in between the clouds and rain,” forecasters said.

Temperatures, meanwhile, will remain about 6 degrees cooler than normal through the weekend.

With rain falling, Los Angeles County health officials issued their standard warning for people to avoid entering ocean water near discharging storm drains, creeks and rivers. An ocean water quality rain advisory will be in effect until at least 7 a.m. Friday.

Health officials noted that stormwater runoff that reaches the ocean can carry bacteria, chemicals, debris trash and other health hazards. People who come in contact with impacted water in the ocean could become ill, health officials said.

More rain was in the forecast early next week, with a chance of showers Sunday through Tuesday, according to the NWS.

Editor’s note: This story has been updated to include information about the state of emergency declaration.