The California fire season has begun in earnest.

Over 11,000 lightning strikes in dry land, in combination with high temperatures, have so far caused more than 350 fires, most of them in a large area around San Francisco.

South of the city, halfway to Los Angeles, a helicopter pilot died outside the city of Coalinga when his helicopter crashed during a firefighting operation.

Half an hour for evacuation

The worsening fires north and west of San Francisco are threatening vineyards in the Napa Valley and have destroyed about 50 properties near Vacaville. Thousands of residents in the city have been evacuated in recent days. Even in Fairfield, on the Pacific coast, several thousand have been forced to evacuate. According to the Daily Republic, they received only half an hour's warning before leaving their homes.

"These are fires on a scale we have not seen in many, many years," said Governor Gavin Newsom, who has declared a state of emergency and asked for help from other states.

"We are putting all the available resources we have to protect communities as California now fights fires around the state in extreme weather conditions," he said.

Smoke in San Francisco

The San Francisco Chronicle reports that the smoke is visible and felt in the big city, and that residents there and in the surrounding Bay Area can count on the smoke remaining for the "foreseeable future".

Colorado has also been hit by forest fires. The second largest fire in the state's history is raging just over 20 kilometers north of the city of Grand Junction. Thunderstorms are behind the fire of over 50,000 hectares.