OAKLAND, Calif. - Cooling fog rolled back into Northern California Friday after an unusual midweek heat wave sent scores of people to the hospital and was partly blamed in at least one death.
Authorities were investigating whether eight other deaths were due to the heat since temperatures shot past 100 Wednesday. Many of the dead were old or frail, making it hard to determine if heat was to blame.
In the one confirmed heat-related death, a 73-year-old man, Cam Bo Tu, collapsed while out walking Wednesday in Alameda County, east of San Francisco. A heart attack was the primary cause of death, but exposure was also listed as a factor, a coroner's spokeswoman said.
When San Francisco, where temperatures usually hover in the 60s, hit 103, there was no doubt the unusual heat created widespread distress, particularly among the elderly.
''All of the counties that we talked to reported that there were significant increases in emergency ambulance traffic,'' said Art Lathrop, director of emergency medical services for Contra Costa County.
The heat buckled the pavement on the freeway linking San Francisco and Sacramento and also caused power outages and so-called ''rotating brownouts'' that left 97,000 customers in the dark.
''We're really having what I would call a heat storm,'' Pacific Gas & Electric spokesman Tom Collins said.
At a San Francisco Giants game Wednesday, 34 people were treated for heat exhaustion and one person was hospitalized for heat stroke with a body temperatures of 106 degrees.
On Thursday, temperatures tumbled back to normal, the high in San Francisco at noon was 61 degrees, 42 degrees lower than the day before.
Lathrop said his office will be tuning up contingency plans should severe weather break out again.
''It's not even summer yet,'' he said. ''It's spring.''