Thick smoke that held down winds and temperatures began to clear Sunday from the scenic forestlands of Northern California as firefighters battling the largest single wildfire in state history braced for a return of fire-friendly weather.

The winds weren’t expected to reach the ferocious speeds that helped the Dixie Fire explode in size last week. But they were nonetheless concerning for firefighters working in unprecedented conditions to protect thousands of threatened homes.

California workers’ compensation written premium for the first quarter of 2021 was 13% below that for the first quarter of 2020, according to a quarterly experience report issued on Wednesday by the Workers’ Compensation Insurance Rating Bureau of California.

The WCIRB report is an update on California statewide insurer experience valued as of March 31.

California will require millions of health care workers and state employees to show proof of a COVID-19 vaccination or get tested weekly, announcing a broad measure this week to try to slow rising coronavirus infections in the nation’s most populous state, mostly among the unvaccinated.

The new rule, to take effect next month, is the latest example of California and politically progressive cities nationwide cracking down on a virus that has upended life since March 2020. New York Mayor Bill DeBlasio announced a similar plan Monday that requires 340,000 city employees, including teachers and police officers, to show proof of vaccination or undergo weekly testing.

It could be days before officials will be able to assess the damage done to a small town by California’s largest wildfire, one of dozens of blazes scorching lands across the U.S. West.

Over the weekend, the massive Dixie Fire roared through the remote Northern California community of Indian Falls. The blaze had already leveled at least 16 houses and other structures, but a new damage estimate wasn’t immediately available because flames were still raging in the mountain area on Monday.

“Fire behavior has been so unpredictable, it hasn’t been safe for inspectors to go in to work,” said Mitch Matlow, a fire spokesman. “Until things settle down, we won’t know the extent of what’s burned.”

A lightning strike likely ignited a 2020 wildfire in California’s Sierra National Forest, but the U.S. Forest Service said Friday it could not determine an official cause of the fire.

September’s Creek Fire burned 600 square miles and spread so quickly that hundreds of Labor Day holiday campers had to be rescued by a series of harrowing helicopter flights. All 214 campers were delivered safely.

Investigators did not rule out arson and lit cigarettes as the cause, but said there were no illegal marijuana grow sites nearby that could have started the fire. Forest service officials said an “undetermined” status is not uncommon with a fire this complex.

California power company Pacific Gas and Electric said on Wednesday it would bury 10,000 miles of power lines in high-risk fire zones as a safety measure after its equipment caused multiple destructive wildfires over several years.

The utility, which called the project a multi-year initiative, maintains more than 25,000 miles of overhead distribution power lines in the highest fire-risk zones, or more than 30% of its total distribution overhead system, according to the company.

The move by PG&E comes days after it said its equipment may have been involved in the start of a recent wildfire in Sierra Nevada, according to a filing by PG&E to regulators published on the internet by a San Francisco Chronicle journalist.

Pacific Gas & Electric reported to California utility regulators that its equipment may have been involved in the start of a fire burning in the Sierra Nevada that is threatening hundreds of homes.

PG&E said in a report Sunday to the California Public Utilities Commission that a repairman responding to a circuit outage on July 13 spotted blown fuses in a conductor atop a pole, a tree leaning into the conductor and fire at the base of the tree.

The utility said its system showed around 7 a.m. that the Cresta Dam off Highway 70 had lost power but because of the steep, rough terrain, the worker sent to check it couldn’t reach the area until nearly 5 p.m.

It may have been around 2017 when a true sense of urgency donned on insurers, public officials, residents and regulators in wildfire-prone California, as fires destroyed or damaged more than 10,000 structures in the state, a higher tally than the previous nine years combined.

In terms of property damage, 2017 was the most destructive wildfire season on record in California at the time, with 9,133 fires burning more than 1.2 million acres, and it was after 2017 that the word “mitigation” seemed to appear more prominently and more often in public messaging about wildfires – along with news of warnings about rising homeowners insurance rates, increasing non-renewals, and of course climate change.

A magnitude 5.1 earthquake struck off the Northern California coast late Saturday, the U.S. Geological Survey confirmed.

The earthquake just before midnight was about 12 kilometers west of Petrolia in Humboldt County and 56 kilometers southwest of Eureka, according to the USGS.

The depth was just over 30 kilometers.

Cal/OSHA is cautioning California employers to be prepared to protect workers from unhealthy air due to wildfire smoke.

When workers are at risk form unhealthy air from wildfires, California’s protection from wildfire smoke standard requires employers to take steps such as changing the location of work operations, modifying work schedules or providing proper respiratory protection like N95 respirators.

According to CalFire, there have been over 4,000 wildfire incidents so far in California in 2021 and more than 100 structures have been damaged. Smoke from these wildfires contains chemicals, gases and fine particles that can harm health.

One of the most harmful hazards comes from breathing fine particles in the air (called PM2.5), which can reduce lung function, worsen asthma or other existing heart and lung conditions, and cause coughing, wheezing and difficulty breathing, according to Cal/OSHA.