National Weather Service United States Department of Commerce

Historic Heat Wave: July 12-15, 1995

South-central and Southeast Wisconsin experienced a historic heat wave during the period of July 12-15, 1995, that resulted in 71 directly-related heat deaths, and 70 indirectly-related deaths.  For the entire 1995 summer, there were 82 directly-related heat deaths, and 72 indirectly-related deaths for a total of 154 heat-related deaths.

Temperatures during the July, 1995 heat wave pushed into the 100 to 105 range across South-central and Southeast Wisconsin, while muggy air with dewpoints in the upper 70s to lower 80s added to the discomfort.  The combination of heat and humidity resulted in heat index values peaking in the 120 to 128 range; probably the highest values in Wisconsin recorded history.

The duration of the heat wave and the stuffy overnight conditions amplified its affects on humans, since it became difficult to recover at night from the daytime affects of the heat.

When the heat index is 105 or higher, a sizable portion of the general population starts to feel the affects of the heat, especially those persons on certain medications, the elderly, and the young.  It's safe to say that when the heat index gets into the 115 to 120 range, or higher, most of the general population is affected, to some degree, by the heat and humidity.

Currently, the five National Weather Service (NWS) Offices that service Wisconsin issue Excessive Heat Warnings when heat index values are expected to reach or exceed 105, while night-time heat index values stay at or above 75, for a period of at least 48 hours.  Heat Advisories are issued when the heat index value is expected to reach 100 to 104, for any time duration.

Below is information from a NOAA press release entitled "Commerce News" that summarizes a report on the historical heat wave that affected not only Milwaukee but the Chicago area.

The number of deaths that occurred during the July 1995 heat wave exceeded the average number of lives lost each year in the United States to floods, hurricanes, and tornadoes -- and many of these deaths could have been avoided, according to a Disaster Survey Report issued today by the National Oceanic and Atmospheric Administration.

More than 1,000 people died during the July 1995 heat wave that hit the Midwest and many cities along the East Coast.  In a normal year, about 175 Americans succumb to the demands of summer heat.

Chicago experienced its worst weather-related disaster, with 465 heat-related deaths recorded during the period from July 11-27, 1995.  Milwaukee was also severely affected, with 85 heat-related deaths recorded during the same time period.

"In both Chicago and Milwaukee, the National Weather Service issued warnings of the developing heat wave several days in advance, which were quickly broadcast by the local media," said Kathryn D. Sullivan, former National Oceanic and Atmospheric Administration chief scientist and leader of the national disaster survey team that investigated this event.  "Given this advance warning, many, if not all, of the heat-related deaths associated with this event were preventable."

So what went wrong?  According to the report, in Chicago and Milwaukee, a heat wave of this magnitude is so unusual that it was not immediately recognized as a public health emergency.  The heat wave was a highly rare -- in some respects an unprecedented -- weather event because of its unusually high maximum and minimum temperatures and accompanying high relative humidities. "Unfortunately, a heat wave connotes discomfort, not violence; inconvenience, not alarm," said Sullivan.

Despite accurate National Weather Service warnings and advisories and effective media coverage, the report concludes people either did not receive or know how to use the information.  Both Chicago and Milwaukee had extensive disaster preparedness plans for other weather events like floods or blizzards.  However, due to the highly rare nature of the heat wave, neither city possessed an official plan for responding to heat emergencies.

The report recommends that the NWS focus preparedness efforts towards people who are most vulnerable to the dangers of heat.  Among the most susceptible are the isolated elderly living in urban areas.  This is because cities such as Chicago and Milwaukee have many urban dwellings constructed of materials such as brick that may trap hot, humid air at dangerous levels.

The report also recommends that emergency response organizations at the federal, state and local levels recognize severe heat waves as potential natural disasters, and that areas at risk should be prompted to develop emergency response plans for severe heat waves.

After a significant weather event, such as a heat wave, a disaster survey team may be assigned by NOAA to evaluate the role played by the National Weather Service, provide an objective appraisal about NWS performance, and make findings and recommendations.  The team's report on the July 1995 Heat Wave is available through the National Weather Service home page on the Internet at: .

Note:  the NWS offices that service Wisconsin, in conjunction with the Wisconsin Emergency Management team, the Milwaukee Health Department, and State and County Health Department departments, conduct an annual Heat Awareness Day in mid-June each year that highlights the dangers of extreme heat.  The media does an excellent job of publicizing this information.  Additionally, a variety of outreach programs have been established by various local and county departments to notify or assist people who may need help during heat waves.  Because of these efforts, very few Wisconsin residents have died due to the affects of excessive heat since the 1995 summer.