State officials declared a state of emergency Wednesday in advance of a two-day storm that's expected to douse much of Northern California. Santa Clara County also issued a local emergency declaration due to storm conditions and risks to the public and property.

The state of emergency proclamation, issued by Gov. Gavin Newsom, authorizes the California National Guard to provide disaster response, directs Caltrans to request immediate emergency assistance from the Federal Highway Administration for potential highway repairs and approves the use of state-owned properties like fairgrounds to stage debris due to the storm and shelter those who are displaced.

The entire Bay Area is under a flood watch and high wind advisory due to the storm, which is expected to last into Thursday and dump several inches of rain across the region with wind gusts as high as 70 mph in some areas.

"California is mobilizing to keep people safe from the impacts of the incoming storm," Newsom said in a statement. "This state of emergency will allow the state to respond quickly as the storm develops and support local officials in their ongoing response."

Experts with the National Weather Service have forecasted that the storm will result in major flooding, mudslides, downed trees and power outages.

"A lot of our trees are stressed after three years of intensive drought," California Department of Water Resources Director Karla Nemeth said Wednesday morning during a briefing on the storm. "The ground is saturated and there's a significant chance of downed trees that will create significant problems."

State residents are urged to avoid driving during the strongest part of the storm, Wednesday evening through Thursday morning, unless travel is essential. Those who do have to drive are encouraged to visit quickmap.dot.ca.gov for live traffic information.

State residents can call 211 or 311 for information about emergency response and alerts. Residents can also sign up for emergency alerts and evacuation notices at calalerts.org.

Santa Clara County's declaration issued on Wednesday night was called due to the following conditions: soils being near or at their saturation point; creeks, streams, and rivers reaching or exceeding flood stage; and low-lying areas experiencing flooding, including road crossings. There is an increased risk of rocks and sediments dislodging from the hillsides. Driving will be challenging during periods of gusty winds, especially for high-profile vehicles, including emergency response vehicles, the county Emergency Operations Center said in a statement.

"This emergency declaration allows the County of Santa Clara to take appropriate measures to support the regional emergency response and ensure the safety of those who live and work in our jurisdiction," county executive Jeff Smith said.

Community members are encouraged to stay off of roads and away from creek beds, waterways and fast-moving waters.

Read more of our storm coverage:

• Palo Alto storm watch: Track the impact of the Jan. 4 atmospheric river event

• Palo Alto residents urged to prepare properties now ahead of rapidly approaching storm

• As storm advances, locals work to protect their homes

• Heavy storms, flood risks renew sense of urgency over delayed San Francisquito Creek projects