Two Ontario men are on their way to Houston to help a family member who has been forced from her home by flooding in the hurricane-battered city.

Bill Hamilton and Pat Quirk left Guelph, Ont., on Monday night after buying an extreme terrain vehicle capable of driving and floating on water, and are on their way to Quirk's sister.

The pair plan to pick up Quirk's sister from the hotel where she has taken refuge, check on her home, and work out a plan to find her a safe place to stay.

Hurricane Harvey made landfall along the Gulf Coast on Friday night as a Category 4 storm and moved northeast along the Texas coast over Houston. The storm has dumped more than 76 centimetres of rain in parts of Texas and authorities have rescued thousands of people left stranded by the storm.

Quirk's 47-year-old sister, who has lived in Houston for a year, was initially stuck in her Houston home, where the ground floor had flooded, Hamilton said. She was helped from her home by a passing motorist and taken to a hotel, but staff have warned guests that the building will likely lose power soon, Hamilton said.

Quirk's sister sent her brother pictures of the hurricane's aftermath early Monday, Hamilton said. Those photos alarmed Quirk and made the 52-year-old decide to go to the city to help his sister, Hamilton said.

When Quirk called Hamilton to tell him of his plan, Hamilton, a 47-year-old landscaper, said he wanted to help out.

"It kind of hit close to home with his sister being there, so I thought I'd give (him) a hand," Hamilton said in a phone interview as he and Quirk made their way to Houston in a pickup truck.

By early Tuesday afternoon, Hamilton said he and his friend were driving through Arkansas, and expected to be in Houston late Tuesday.

"We're in contact with (Pat's) sister now and trying to make a plan as to what part of the city we head for first," Hamilton said.