Excessive heat warning issued as mercury rises

Tuesday, July 12, 2005 | 10:48 a.m.

Health officials offer this checklist of what to do during the Las Vegas heat wave:

Source: Centers for Disease Control and Prevention in Atlanta.

The National Weather Service issued an excessive heat warning for today and Wednesday as temperatures were expected to climb at least five degrees above Monday's high of 106 degrees, forecaster Barry Pierce said.

The warning is issued when predictions indicate daytime highs close to record-high temperatures.

Record temperatures for today are 114 degrees, set in 2003, and for Wednesday 115 degrees, set in 1939, according to Weather Service records.

The Weather Service expects a high of 111 degrees or hotter in Las Vegas today and 112 degrees or higher Wednesday, Pierce said.

Along the Colorado River and Lake Mead temperatures could approach 118 degrees and between 120 and 125 degrees for Death Valley in Southern California.

Southern Nevada's heat wave is caused by high pressure, a pool of still air sitting atop the valley like a dome. The surface air moves little or not at all.

Heat-related illnesses can range from minor ailments such as heat rash to heat stroke, a life-threatening condition, said Dr. Donald Kwalick, chief health officer for the Clark County Health District.

Some people are more vulnerable to heat than others, said David Tonelli, spokesman for the health district.

"The very young, the very old and those with health-related complications are at greatest risk," Tonelli said Monday.

According to coroner's office records, heat stress has killed a total of 64 people in Southern Nevada in the past three years -- 12 deaths in 2004 and 26 each in 2003 and 2002. There have been no heat-related deaths reported this year.

Heat can affect even young and healthy people participating in strenuous physical activities during hot weather.

Also drinking alcohol and taking medications that impair the body's ability to regulate temperature or inhibit perspiration put people at risk from heat.

The best advice the Health District has focuses on staying indoors with air conditioners running during peak heat of the day, Tonelli said.

Avid exercisers and those who have to be outdoors should go before noon or after sunset, when dry desert air tends to cool a few degrees, Tonelli said.

For those active under the sun's blazing rays, drink two to four glasses of water every hour, Tonelli said.

Beverages should not include alcohol or caffiene as both contribute to dehydration, he said.

Fruit juices and sports drinks help replace salts and minerals lost during outside activity in the heat, Tonelli said. But water is still the No. 1 thirst quencher.

The heat warning includes pets. Veterinarians recommend keeping animals indoors during the worst heat. If a dog or cat must be outside, provide plenty of drinking water, food and shaded areas for the pets.

Las Vegas forecasters at the Weather Service use a new system to accurately warn residents sooner before conditions threaten to turn deadly.

A "warning" is issued in cases of extreme heat with the potential to sicken or kill.

Urban areas are at a greater risk for severe heat. Black-tar roads, rooftops and metropolitan activities all contribute to severe heat.

Fewer trees and more pavement can kick the thermometer higher, creating an "urban island" effect. The Weather Service in Southern Nevada said in the mid 1990s that Las Vegas had raised its temperature by a degree or two from the effects of urbanization.

Triple-digit temperatures were forecast across much of Northern Nevada through Wednesday, and the news has fire officials worried.