Heat Waves are a series of days or temperatures that create a safety hazard for anyone exposed to the heat. A heat wave can be an extended period of days with higher than normal temperatures. A heat wave can also be shorter in length, but with abnormally high temperatures.
Any time a person is exposed to heat, they are in danger of suffering from heat exhaustion and heat stroke. These heat-related illnesses have killed thousands over the last 100+ years. For example, in 1980, a heat wave in the United States killed more than 1,250 people. That is nothing compared to the 50,000+ that died in the European heat wave of 2003. Each was considered a billion dollar weather disaster because, in addition to the excessive heat, there were also drought conditions that accompanied the heat wave.