A helicopter pilot died on Wednesday when his aircraft crashed while fighting one of hundreds of wildfires raging in California after lightning storms.

California was hit by nearly 11,000 lightning strikes in 72 hours, sparking 367 fires, with over 50 structures destroyed in Northern California’s wine country where thousands fled their homes, authorities said.

In central California, a helicopter was on a water dropping mission in Fresno County about 160 miles (258 km) south of San Francisco when the aircraft crashed, killing the pilot who was the only person aboard, the California Department of Forestry and Fire Protection said in a statement.

To the north of San Francisco, a group of fires covering over 46,000 acres (18,615 hectares) near the city of Vacaville raced through hills and mountains, destroying 50 homes and other structures.

The city of 100,000, about 30 miles southwest of Sacramento, was under a partial evacuation order after flames from the LNU Lightning Complex fire burned west side homes, leaving dead livestock among the properties or wandering around, a Reuters photographer said.

To the south, police gave communities west of Fairfield, a city of 117,000, about 30 minutes notice of mandatory evacuations, the Daily Republic newspaper reported.

“We are experiencing fires the like of which we haven’t seen in many, many years,” California Governor Gavin Newsom told a press conference, adding that he had requested 375 fire engines from out of state.

Fanned by “red-flag” high winds, fires sparked by dry-lightning from rainless thunderstorms are sending flames racing through vegetation parched by a record-breaking heat wave and low humidity.

The blazes follow devastating fires across Northern California in 2017 that killed 44, wiped out numerous wineries and destroyed nearly 9,000 homes and other structures.

A group of fires called the SCU Lightning Complex, centered about 20 miles east of Palo Alto, more than doubled in size overnight and is now burning over 85,000 acres. The CZU August Lightning Complex, meanwhile, has grown to over 10,000 acres and forced evacuations around 13 miles south of Palo Alto.

To the west, drought stricken Colorado faced its second-largest wildfire in history on Wednesday. The Pine Gulch blaze has produced its own weather system with thunder and lightning as it burned across 125,100 acres. It covers an area larger than the city of Denver, in remote mountain terrain about 20 miles north of Grand Junction, authorities said.