A fleet of monster trucks has been helping rescue efforts in Texan cities hit by Hurricane Harvey.

Volunteer Josh James recruited his friends from Dallas racetrack, Rednecks with Paychecks, to drive five monster trucks to flooded areas.

One large-wheeled vehicle was filmed pulling an army truck from the flood waters in Copperfield, northwest Houston, in front of a cheering crowd.

Mr James, a mechanic, said that along with other volunteers, he had to swim up to second stories of buildings to rescue people trapped in their homes.

"When people need help and I can help, I'm out there," he told ABC News.

The monster trucks have also helped to get emergency services personell into areas where the flooding is most severe.

At least 31 people have died after the most powerful storm to hit Texas in more than half a century years brought record levels of flooding to Houston and the surrounding areas.

The fleet of modified vehicles was part of a larger response to the disaster, involving 200 boats, 300 lorries and 600 people.

Local news broadcasts and social media posts are helping coordinate the response.

The aftermath of Hurricane Harvey Show all 19 1 /19 The aftermath of Hurricane Harvey The aftermath of Hurricane Harvey A tattered U.S. flag damaged in Hurricane Harvey, flies in Conroe, Texas Reuters The aftermath of Hurricane Harvey Lisa Rehr holds her four-year old son Maximus, after they lost their home to Hurricane Harvey, as they await to be evacuated with their belongings from Rockport, Texas Reuters The aftermath of Hurricane Harvey People line up for food as others rest at the George R. Brown Convention Center AP Photo/LM Otero The aftermath of Hurricane Harvey Volunteers with The American Red Cross register evacuees at the George R. Brown Convention Center Reuters/Nick Oxford The aftermath of Hurricane Harvey Soldiers with the Texas Army National Guard help the residents of Cyprus Creek Reuters The aftermath of Hurricane Harvey Residents wade through floodwater Reuters/Nick Oxford The aftermath of Hurricane Harvey Residents walk along the flooded roadway of Texas 249 as they evacuate their adjacent neighborhoods EPA The aftermath of Hurricane Harvey A man floats past a truck submerged on a freeway flooded by Tropical Storm Harvey on Sunday AP The aftermath of Hurricane Harvey People are rescued by airboat as they evacuate from flood waters from Hurricane Harvey in Dickinson, Texas Reuters The aftermath of Hurricane Harvey James Archiable carries his bike through the flooded intersection at Taylor and Usenet near downtown Houston, Texas EPA The aftermath of Hurricane Harvey A massive sinkhole opened up on a motorway in Rosenburg, a city 25 miles southwest of Houston, Texas Rosenberg Police The aftermath of Hurricane Harvey People are rescued from flood waters from Hurricane Harvey in an armored police mine-resistant ambush protected vehicle in Dickinson, Texas Reuters The aftermath of Hurricane Harvey People are rescued from flood waters from Hurricane Harvey on a boat in Dickinson, Texas Reuters The aftermath of Hurricane Harvey Evacuees are airlifted in a US Coast Guard helicopter after flooding due to Hurricane Harvey inundated neighborhoods in Houston, Texas Reuters The aftermath of Hurricane Harvey Evacuees leave a US Coast Guard helicopter after being rescued from flooding due to Hurricane Harvey in Houston, Texas Reuters The aftermath of Hurricane Harvey Residents look on at a submerged motorway during a break in the rain in Houston, Texas EPA The aftermath of Hurricane Harvey People photograph the submerged motorway interchange EPA The aftermath of Hurricane Harvey Debris lies on the ground after a building was destroyed by Hurricane Harvey in Aransas Pass, Texas AP The aftermath of Hurricane Harvey Dominic Dominguez searches for his boat in a boat storage facility that was heavily damaged by Hurricane Harvey near Rockport, Texas EPA

An estimated 24.5 trillion gallons of rain have fallen on the US Gulf Coast since the hurricane hit. Harvey has since been downgraded to a tropical storm.

Tens of thousands of people have been evacuated from their homes after Houston and the surrounding areas were hit by unprecedented levels of flooding.