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The Urban Heat Wave

How a hot summer day is the city’s most underreported killer

    Chicago felt tropical, like Fiji or Guam but with an added layer of polluted city air trapping the heat. On the first day of the heat wave, Thursday, July 13, the temperature hit 106 degrees, and the heat index—a combination of heat and humidity that measures the temperature a typical person would feel—rose above 120. For a week, the heat persisted, running between the 90s and low 100s. The night temperatures, in the low to mid-80s, were unusually high and didn't provide much relief. Chicago's houses and apartment buildings baked like ovens. Air-conditioning helped, of course, if you were fortunate enough to have it. But many people only had fans and open windows, which just recirculated the hot air.  The city set new records for energy use, which then led to the failure of some power grids—at one point, 49,000 households had no electricity. Many Chicagoans swarmed the city's beaches, but others took to the fire hydrants. More than 3,000 hydrants around Chicago were opened, causing some neighborhoods to lose water pressure on top of losing electricity. When emergency crews came to seal the hydrants, some people threw bricks and rocks to keep them away. The heat made the city's roads buckle. Train rails warped, causing long commuter and freight delays. City workers watered bridges to prevent them from locking when the plates expanded. Children riding in school buses became so dehydrated and nauseous that they had to be hosed down by the Fire Department. Hundreds of young people were hospitalized with heat-related illnesses. But the elderly, and especially the elderly who lived alone, were most vulnerable to the heat wave...... —Eric Klinenberg, author of Heat Wave: A Social Autopsy of Disaster in Chicago

    Listening to Eric Klinenberg’s description, it sounds like the
screenplay for Hollywood’s latest sci-fi thriller, but it actually
happened here in Chicago—and not so long ago. It was the deadly heat wave of 1995, when as many as 740 people may have died of heat- related illnesses during one week in July. No one can be sure of the exact number, but it ranks among the worst disasters in the city’s history, perhaps second only to the 1915 U.S.S. Eastland ship accident (844 deaths) and ahead of the 1903 Iroquois Theater fire (602 deaths) and the infamous 1871 Chicago fire (300 deaths).
    With summer upon us, it is time to prepare for the deadliest of
all weather emergencies—urban heat waves. While hurricanes,
tornadoes, floods and lightning get most of the television time and newspaper headlines, heat waves are more deadly than any of those calamities. In the decade from 1992 to 2001, more persons in the United States died from excessive heat than from those other four causes combined. In contrast to even a small number of deaths during a tornado or hurricane, any deaths due to the effects of heat are rarely reported until a prolonged heat wave affects a highly populated area.
    This relative lack of notoriety feeds on itself. Even in urban
areas, when people begin to succumb to excessive heat, the public is slow to take note. Many of those who die do not die directly from heat stroke; they are often victims of an increased incidence of cardiovascular disease as hot weather takes its toll on the heart.  These deaths may not be considered heat-related. Further, mortality tends to occur in groups in where death is not considered unusual—those at the extremes of age, the infirmed and the grossly obese.
    Studies have shown that perhaps the greatest risk factor for
death during hot weather is social isolation. Consider the elderly
shut-in or the mentally disturbed individual on psychiatric
medication; these are victims unlikely to attract undue attention.
    In his writings and interviews, Klinenberg has referred to a
relevant study from the American Journal of Public Health, which said most climate models “failed to detect relationships between the weather and mortality that would explain what happened in July 1995 in Chicago.” He noted that many victims were senior citizens who died alone, behind locked doors and sealed windows, out of contact with friends, family, neighbors, public agencies or community groups.  He and others have pointed out the possible association of social factors, including dangerous neighborhoods where there may be a distrust of neighbors and a fear of leaving the house, as well as the danger of living in a one-room dwelling or other low-income housing without air conditioning. (I experienced a particularly disconcerting example of the lack of air conditioning during the heat wave. The inner city hospital where I worked lacked central air conditioning, and at least two persons were found dead in their hospital beds, victims of what was probably unrec-ognized and unreported heat stroke.)
    In fairness, Chicago should not be singled out. The same 1995
heat wave affected Milwaukee, 90 miles to the north, and nearly 200 people may have died, a figure that is nearly comparable considering the smaller population. The pattern of mortality was also similar to that observed in Chicago. In a 2003 European heat wave, more than 50,000 people perished, a disproportionately high number being French senior citizens living in homes without air conditioning.
    Heat-related emergencies call for a concerted response by local government, and the 1995 heat wave made government officials realize the city must mobilize its resources to prevent hundreds of deaths. Before that event, the general public was unaware of just how dangerous heat waves could be. In similar weather in earlier decades—Chicago suffered through several brutal summers in the 1930s—heat-related deaths were underreported, and without television and the internet, details were not widely disseminated to the public. In 1995, wider media coverage criticized government officials in Chicago (and Milwaukee, as well as in France in 2003) for their slow response and lack of action. Much of that criticism was legitimate. Until then, no one truly appreciated the gravity of the situation.
    During the heat wave, the number of persons who died when
temperatures rose above 100°F was initially undercounted. It wasn’t until funeral homes and morgues started reporting tremendous increases in corpses—they literally began running out of space—that there was a systematic approach to counting the number of individuals who were dying as a result of the heat. By that point, several hundred excess deaths had been recorded, and the response was somewhat haphazard for several days. (The patient I remember most vividly during the heat wave was a young man who worked pouring hot tar on a roof. On the hottest day of the heat wave, when the temperature reached 106 and the heat index reached 125 at Midway, he was brought in with heat stroke and a body temperature of 111. He was critically ill for several days, but survived. He was lucky—that high a body temperature is usually fatal.)
     Since then, to their credit, Mayor Richard Daley and his staff
have learned their lessons well. The city currently works in concert with the National Weather Service, private meteorologists and community organizations. If temperatures in Chicago are forecast to exceed 90°F for any prolonged period, a series of graded warnings are issued on television, radio and in the newspapers. Private and public resources are mobilized so that air conditioned cooling centers are made available to the public with transportation available to those unable to travel. The public and the police are encouraged to check on their neighbors, especially the elderly and infirmed. Public health officials and hospitals are alerted to watch for early patterns of emergency room admissions and deaths. Every summer Chicago has a “Heat Awareness Week” to prepare the population for hot weather emergencies. So far, this approach seems to have worked in reducing heat-related mortality.
    While Chicago has not had a prolonged heat wave comparable to that of 1995, in several less severe heat spells there has been no drastic increase in mortality during the events. In a 1999 heat wave, the city responded with their full-scale heat emergency plan—strongly worded warnings and press releases to the media, cooling centers, free bus transportation to seniors, phone trees to elderly residents and police officers and city workers checking door-to-door on shut-ins. Public health officials were pleasantly surprised at the success of the operation, and it has been augmented since then. Today, there may be no North American city better prepared for a heat emergency than Chicago.
    Individuals must use common sense when the temperature rises above 95° F, especially when the humidity or dew point is high. Even a few degrees increase of temperature at that point can be extremely dangerous for outdoor activity or people who are not in an air-conditioned environment. Health officials constantly advise people who must be outside to wear loose, light fitting clothing and drink plenty of fluids. It’s also important to curtail all unnecessary activity outside when temperatures become oppressive. Every summer, runners and young adults engaged in physical activity are susceptible to heat-related illnesses.  Activities like football practices and outdoor games should be curtailed, postponed or when possible moved indoors or to after sundown. People should avoid going outdoors as much as possible; those without air conditioning should seek air-conditioned shelters. Check in on neighbors who you suspect may have difficulty dealing with the heat. The major lesson the 1995 Chicago heat wave taught us is that we’re all under the sun together.

Published: June 07, 2009
Issue: Summer 2009 Urban Living