BRENTWOOD -- Triple-digit temperatures across the East Bay sent unprepared people to the hospital and stretched emergency responders thin Saturday.
More than two dozen people at two East Contra Costa high school graduation ceremonies were treated for heat-related emergencies Saturday morning, leading firefighters to treat one event like a multicasualty incident, the fire chief said.
With the National Weather Service reporting a temperature of 104 in Brentwood shortly after noon Saturday, attendees at outdoor graduations at Heritage High in Brentwood and Freedom High in Oakley began dropping like flies, East Contra Costa Fire District Chief Hugh Henderson said.
"As crews started treating one patient, they would get reports of others not feeling well either," he said.
Heritage High was declared a multicasualty incident, and at least nine ambulances and three engines were sent to the school.
By the end of the ceremony, 17 patients were treated for heat-related emergencies, with 11 transported to hospitals, Henderson said.
At Freedom High, which also celebrated graduation on the football field, eight patients were treated, with one transported to a hospital.
School officials were not immediately available for comment.
"If I could tell anyone anything today it's to stay hydrated," Henderson said.
American Medical Response ambulances were stretched thin Saturday due to heat-related calls, Henderson and dispatchers said.
In Livermore, where temperatures reached 102 degrees by 1 p.m., Livermore Rodeo attendees braved the heat. Organizers anticipated the heat wave and set up a cooling station with misters, said the rodeo's associate director, Polly Stonich. She said no problems were reported.
The intense heat wave did not just affect the Bay Area -- at least two people were critically sickened at a morning graduation ceremony at Del Oro High School in Loomis, forcing school and fire officials to cancel the event, according to the Sacramento Bee.
Many of the 15 stricken, who ranged in age from 15 to 80, suffered heat exhaustion and heat stroke.
The Bay Area Air Quality Management District declared Saturday its third Spare the Air Alert of the year. Air quality was expected to be poor due to high temperatures and low winds.
Though temperatures are expected to drop more than 20 degrees Sunday, the National Weather Service did issue a dry lightning warning for much of the East Bay.
Between 11 a.m. and 8 p.m. Sunday, dry thunderstorms -- thunder and lightning, but no rain -- could occur from Santa Rosa through Contra Costa County and down past San Jose, which could lead to quickly spreading fires.
Contact Matthias Gafni at 925-952-5026. Follow him at Twitter.com/mgafni.