Seattle's high temperature soars to 98 degrees

You may have heard it from your grandmother, or a co-worker who hails from a place where 90-degree summer days constitute a cold snap: "Stop whining. A couple of hot days aren't going to kill you."

Even the National Weather Service office in Seattle used to shrug off the region's rare heat waves, like the one that drove temperatures to a daily record of 98 degrees Wednesday.

But that was before scientists analyzed Western Washington's hottest spells and discovered they really can be deadly.

Larry Kalkstein, research professor of climatology at the University of Miami, compared weather patterns and mortality figures in Seattle and found the death rate climbs 5 percent to 8 percent when temperatures soar.

"It's precisely because these heat waves are so uncommon, and people are not used to it," he said. "Your whole urban infrastructure is ill-adapted to heat because it happens so rarely." In a city like Phoenix, where 95 degrees is the norm in summer, a Seattle-style heat wave wouldn't faze anyone.

Kalkstein's analysis persuaded the weather service in Seattle to adopt a new "heat/health" warning system last year tailored specifically to Western Washington. Kalkstein has helped 18 other U.S. cities develop similar systems.

For each region, he identified the weather conditions most likely to imperil human health. When weather-service meteorologists see those patterns emerging, as Seattle forecasters did this week, they issue "excessive heat warnings."

"We look at the duration of the heat wave, the temperature and humidity," said Brad Colman, meteorologist in charge for the weather service in Seattle. "We look at when the various thresholds are exceeded."

The local weather service used to use a more generic yardstick, called the heat index, to decide when to issue hot-weather alerts. Like the wind-chill factor, the index combines temperature and humidity to calculate a relative heat — an estimate of how hot it feels.

But Seattle, with its moderate climate, never exceeded the one-size-fits-all 105-degree trigger point, which is better suited to the Deep South or muggy Midwest.

This week, local governments in the Puget Sound region responded to the heat/health warning by setting up emergency "cooling centers" where people could escape the heat, but some of them reported only a few people showed up. Health departments and utilities bombarded the media with more than the usual hot-weather safety tips, and warnings went out reminding people not to leave children or pets in cars.

In Philadelphia, where Kalkstein's warning system has been in operation for more than 10 years, he calculates 117 lives were saved over one three-summer period.

Hurricanes, tornadoes and snowstorms may get the most attention, but the National Weather Service says extreme heat is responsible for the most weather-related deaths.

More than 140 people perished during a two-week heat wave in California last year. Ten days of record heat killed tens of thousands across Western Europe in 2003. Chicago's morgue was overwhelmed with 700 bodies when temperatures reached 106 degrees during a 1995 heat wave.

Seattle never sees heat of that magnitude, but the weather service estimates as many as 60 additional deaths here were triggered by high temperatures in 1992.

Few of the fatalities are caused by heat stroke or other obvious heat-related symptoms, Kalkstein said. "It's usually in the form of additional heart attacks, strokes or respiratory failure," he said.

Dr. Scott Barnhart, medical director for Harborview Medical Center, said his emergency department hasn't reported an influx of patients over the past few days. He reserves judgment on Kalkstein's conclusions about the link between heat and deaths, but agrees that high temperatures can aggravate existing health problems, especially for people who are not adapted to the heat.

"The body is designed to run in a really narrow band of temperatures," he said.

Folks in Hoquiam, on the Washington coast, probably felt themselves being squeezed out of that comfort zone Tuesday, when temperatures reached 99 — the town's all-time high.

Like the coast, the Puget Sound region is blessed with beaches and breezes that evaporate the sweat.

Kristin Bautista, 27, of Renton, dropped her toddlers off at an air-conditioned day care to make sure they didn't get overheated. She then cooled off with a swim in Lake Washington at Gene Coulon Memorial Park in Renton.

She sat with her friend Cathy Chavez, 51, of Tukwila, eating lunch on a bench by the beach. Chavez recalled her childhood days in Texas, when an open door meant a suffocating wave of heat.

"We don't get it that much around here," she said. "Enjoy it while it lasts."

Which, the weather service says, won't be much longer. Temperatures today are expected to stay in the 80s. By Sunday, it could be raining.

Staff researcher Gene Balk and staff reporter Cara Solomon contributed to this story. Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com