The National Weather Service has issued an active heat advisory in effect from noon Wednesday, July 4, until 8 p.m. Thursday, July 5 in St. Louis County.

The advisory also affects St. Louis city, Jefferson County, Madison County, St. Charles County, Reynolds County, St. Francois County, St. Genevieve, Iron County and Washington County.

Heat index values of 105 degrees and higher are likely during the afternoon and early evening through Thursday evening. There will be hear index values of up to 107 due to temperatures in the mid-90s, and dew points in the mid-70s. 

St. Louis County is partnering with the Salvation Army to offer a 24-hour cooling shelter from July 2 through Sept. 7, 24 hours a day, seven days a week. The shelter is located at 10740 Page, 63132. The facility can accommodate up to 48 people.

“St. Louis County and the Salvation Army are providing professional services to our most vulnerable residents this summer,” County Executive Steve Stenger said in a news release. “Aside from providing relief from the heat, anyone using the shelter will have access to the Salvation Army’s array of services including meals, laundry facilities and case management to help those in need find housing.”

The combination of hot temperatures and high humidity will likely lead to an increased risk of heat-related stress and illness. The very young, the elderly, those without air conditioning and those participating in strenuous outdoor activities will be the most susceptible. Also, car interiors can reach lethal temperatures in a matter of minutes.

A heat advisory means that a period of hot temperatures and high humidity will occur. This combination will create a situation in which heat-related illnesses are possible, especially for those living in un-airconditioned homes or apartments.

People in the advisory area are advised to avoid poorly ventilated areas and prolonged work in the sun. Also, keep plenty of liquids on hand and try to stay in an air-conditioned environment. Take extra precautions if you work or spend time outside. When possible, reschedule strenuous activities to the early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose-fitting clothing when possible and drink plenty of water. To reduce risk during outdoor work, the U.S. Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air-conditioned environments. Anyone overcome by heat should be moved to a cool and shad ed location. Heat stroke is an emergency, call 911 immediately.

The St. Louis County Office of Emergency Management also reminds residents, “Look before you lock!” Young children and pets should never be left unattended in vehicles under any circumstances. This is especially true during warm or hot weather when car interiors can reach lethal temperatures in a matter of minutes.