( CNN ) -- Texas firefighters were making significant progress Tuesday against wildfires that have consumed at least 78 homes and , at their peak , were burning the length of a football field every minute . Sustained winds of 40 mph , gusting to 60 , combined with 2 % relative humidity in some areas to cause the grass fire conflagration Sunday , said Mark Stanford , chief of fire operations for the Texas Forest Service . On Tuesday , however , firefighters had all 21 remaining fires at least 50 percent contained , Stanford told CNN Radio . Crews want to have them fully contained by Thursday , he said . `` Friday will be another bad day for us , '' Stanford said . `` Not as bad as Sunday , but it will be a very high fire danger day across that region . So we want to make sure that we 've freed up all of our fire resources so that they can respond to new starts we may have . '' As of Tuesday , 78 homes had been reported destroyed , and that number is expected to increase as teams fan out to inspect damages , Stanford said . None of the fires were threatening communities . Smoke from one fire caused an accident that killed a 5-year-old child Sunday on Interstate 20 . Officials believe many of the fires were started by power lines that fell from high winds . Officials are urging citizens to be very cautious with their outdoor activities on fire danger days . One fire was caused by an individual grinding on metal pipe , Stanford said . A blaze in Midland was caused when a vehicle tire blew and the tire rim created sparks . Since Sunday , forestry officials , who were called in to assist local fire departments , have responded to 71 fires covering 136,699 acres , the Texas Forest Service said on its website . Most of the fires were across the Texas Panhandle . The fires occurred in an area of about 45,000 square miles , the size of Kentucky , Stanford said . Two of the biggest active fires were in Randall County , where 26 homes were lost , and Potter County , where 29 homes were lost . Those fires were 80 % and 25 % contained , respectively . Both were expected to be completely contained by day 's end , Stanford said . Potter County Sheriff Brian Thomas said a 61,000-acre fire in his county was ignited when a man cut pipe with a metal grinder in high wind Sunday . Austin Lynn Stephens , 52 , was arrested and charged with criminal trespass because he was on private property when he was using the grinder . Firefighters battled blazes in a dozen other counties , including a 35,000-acre fire in Matador West in Motley County , and a 21,000-acre fire in Andrews County , officials said Monday . They also fought fires in the counties of Haskell , Tom Green , Randall , Howard , Midland , Scurry , Motley , Crockett , Mitchell and Eastland . One wildfire destroyed a dog kennel near Amarillo , Capt . Wes Hall of the Amarillo Fire Department said . Authorities were trying to account Monday for the animals missing or dead after the fire tore through the Willow Creek Kennel . Firefighters were able to open cages to free at least some of the dogs before the flames overtook the facility . As many as 27 homes were destroyed in the area and `` the fire was on the kennel in a matter of minutes , '' employee Chance Smith said , adding he did not have an exact number of dogs lost . In the community of Matador , north of Lubbock , families could do nothing but watch as their homes burned to the ground . Juan and Rosemary Segovia had n't been gone 20 minutes when they returned to a panic-stricken neighborhood and found they had lost everything they owned . `` To know everything you worked so hard for , it 's all gone , '' a tearful Juan Segovia told CNN affiliate KCBD . He and his wife stared in disbelief at the blaze . The family of seven is without a home , but grateful for what was not lost . `` I 'm glad our family was n't home when it happened , '' Rosemary Segovia said before falling into her husband 's arms . `` That 's all I care about is I have my family . '' CNN 's Dave Alsup , Mariano Castillo and Antoinette Campbell and CNN Radio 's Barbara Hall contributed to this report .
NEW : All 21 wildfires are at least 50 % contained , Mark Stanford says . NEW : A fire in Midland is blamed on a vehicle tire that blew , he says . More than 136,000 acres have burned in 71 fires in Texas , the state forest service says . 78 homes have been reported destroyed .