Thousands of drivers have been urged to avoid using their cars in certain areas across three states due to the risk of sparking wildfires.The red flag warning was issued for a string of towns and counties across Kansas, Colorado, and Nebraska by the National Weather Service (NWS), which warned of "critical fire weather conditions" on Monday.Why It MattersThe alerts cover areas spanning three states and are directed at drivers in a bid to avoid wildfires because the heat on the underside of the vehicle could spark a blaze in the brush.What To KnowThe National Weather Service's branch based in Goodland, Kansas, issued a red flag warning on Monday, warning about the heightened risk of fire across three states.Temperatures of up to 82 degrees, with wind gusts up to around 30mph have been forecast, while humidity is expected to be as low as 12 percent. "Any fires that develop will likely spread rapidly," the NWS said, adding: "Outdoor burning is not recommended."A number of fire weather zones across three states were flagged, with drivers in those zones asked to take extra care, such as avoiding driving in areas of grassland because the heat on the underside of the vehicle could spark a blaze in the brush. Motorists were also told to maintain their cars to avoid sparks and to refrain from using tow chains that drag across the ground and create friction.Fire weather zones each have their own three-digit number, and the numbers and corresponding counties affected by the red flag warning are:Kansas: 001: Cheyenne County, KS 002: Rawlins County, KS 003: Decatur County, KS 004: Norton County, KS 013: Sherman County, KS 014: Thomas County, KS 015: Sheridan County, KS 016: Graham County, KS 027: Wallace County, KS 028: Logan County, KS 029: Gove County, KS 041: Greeley County, KS 042: Wichita County, KS 079: Dundy County, NE 080: Hitchcock County, NE 081: Red Willow County, NE 252: Yuma County, CO 253: Kit Carson County, CO 254: Cheyenne County, CO What People Are SayingThe National Weather Service issued a red flag warning, saying: "Critical fire weather conditions are expected across the area... The combination of dry fuels, southwest winds gusting up to 30 mph and low relative humidity will support critical fire weather conditions across the area Monday afternoon." The warning went on to add: "Comply with burn bans and regulations. Avoid driving on dry grass or brush. Maintain vehicle brakes and tires and secure tow chains to avoid dragging. Never toss lit cigarettes onto the ground."The International Association of Fire Chiefs has previously issued a leaflet containing fire safety advice and the section on vehicles reads: "Never throw cigarettes or matches out of a vehicle. They can ignite grasses on the side of the road and start a wildland fire. Do not drive your vehicle in dry tall grass. The underside of your vehicle is hot and can easily ignite grasses from your exhaust muffler. Ensure trailer chains do not drag on the ground."What Happens NextResidents and drivers in the affected areas should check their local weather forecasts and news stations for the most up-to-date advice.