State health officials confirmed five more heat-related deaths Monday as a cool-down ended one of the longest heat waves on record for the region.
The heat killed a total of 18 people during a 12-day stretch of 90- and 100-degree heat, state health officials reported Monday. The latest casualties include an elderly Baltimore County woman, a Baltimore man, two Prince George's County men and a St. Mary's County man. Three other people died during the derecho storm, characterized by powerful winds, on June 29.
Many of the heat victims had underlying chronic conditions such as heart disease or diabetes, and many also may have lacked air-conditioning because of extended power outages, a state health official said. The health department is delving into how much of a role power outages may have played in the deaths, along with other factors that could be prevented in the future. No other information about the victims was available.
Though the extreme heat ended, severe storms continued to cause power outages a day after utility crews finished restoring nearly 750,000 outages caused by the destructive June 29 storm. Early-morning thunderstorms caused 17,000 power outages Monday, most of them restored within a few hours.
But more storms in the forecast may mean more time in the dark for some just days after the last round of outages, some of which lasted more than a week.
During the recent heat wave, state and local health officials sent out frequent messages encouraging residents to check on elderly neighbors and relatives, said Dr. Clifford S. Mitchell, director of environmental health for the state health department. Such checks were particularly important given the widespread power outages, he said.
"Clearly, with some things we're going to go back and look and see whether we can do better next time," Mitchell said. "One of the things we'll want to do is look closely at where there were deaths, were there factors we can learn from those deaths to help us better target messages or interventions for people who might be at risk?"
Heat-related illnesses include hyperthermia, dehydration, heatstroke and heat exhaustion. Chronic illnesses like heart and lung disease, diabetes, and any illness that may cause dehydration or prevent fluid intake can exacerbate heat-related illnesses, Mitchell said. When heat is suspected to have played a role in a death, the state Office of the Chief Medical Examiner studies the bodies to determine whether it was a factor.
Health officials have not determined how the death toll compares to previous heat waves, and Mitchell said it can be hard to do so. The death toll for this month is nearing that of July 2011, the hottest month of July on record in the region, when 23 people died of heat-related illnesses. But spans with a high average temperature, as was the case in July 2011, may not affect health the same way as extreme high daytime temperatures or lack of overnight cooling, Mitchell said.
The 12-day stretch of heat with highs over 90 degrees that ended Sunday was eighth-longest on record in Baltimore, according to the National Weather Service. It ended with three record-setting or tying temperatures — a 104-degree high Saturday and an 82-degree low and 100-degree high Sunday, as measured at Baltimore-Washington International Thurgood Marshall Airport.
The weather service's Sterling, Va., office, which covers the Baltimore area, initially reported the Saturday high as 103 degrees at BWI but later corrected it to 104 degrees. That's because the office issues a preliminary daily climate report around 5:30 p.m. each day based on weather data through about 4 p.m. that day, said Steve Zubrick, science operations officer at Sterling.
BWI recorded a high of 103 degrees at about 3:58 p.m. but later hit the 104-degree mark at 4:16 p.m. Weather service meteorologists can't easily reprogram when their instruments report the high temperature, and the official report for the day doesn't come out until after 1 a.m., when the 104-degree high was made official, Zubrick said.
Monday's high temperature at BWI was 86 degrees; downtown, the Maryland Science Center reached 92 degrees. Highs across the region are expected to remain below 90 degrees through Saturday, though chances for thunderstorms persist throughout the week.
The storms that struck late Sunday and early Monday caused less damage than Baltimore Gas and Electric Co. officials expected, said Rob Gould, BGE spokesman. The most severe weather tracked south of the Baltimore area as a cold front moved across the region. Power outages were scattered, mostly across Anne Arundel and Baltimore counties and Baltimore City.
Forecasts had called for an elevated chance of severe weather developing along the edge of a cool front that moved across the state overnight and cooled temperatures Monday. The strongest storms tracked across Southern Maryland.
"Based on the forecast, we expected higher numbers," Gould said. "But, fortunately, the storm was nowhere near as severe as what was experienced south of our area."
BGE officials couldn't say how many of Monday's outages affected customers who also lost power after the June 29 storm. It was possible some of those who coped with outages for as much as a week were affected again, but without specific addresses the company could not come up with an accurate number, spokeswoman Rachael Lighty said.
About 170 overhead line workers, part of out-of-state emergency crews, remained in the state Monday to assist in the repairs, Gould said. About 1,900 workers from outside the state helped to make repairs following the June 29 storm.
An earlier version of this article misstated the number of workers brought in from outside Maryland to assist BGE crews. The Sun regrets the error.
Sun reporter Mary Gail Hare contributed to this article.
Heat wave by the numbers
18: Heat-related deaths confirmed since July 2 in Maryland
104: High temperature at Baltimore-Washington International Thurgood Marshall Airport on Saturday
12: Consecutive days, ending Sunday, with highs of 90 degrees or higher in the Baltimore region
8: Rank of the heat wave among the longest stretches on record with high temperatures 90 degrees or higher at BWI