Many of the millions left without power when Hurricane Beryl crashed into Texas, killing several people and unleashing flooding, now face days without air conditioning as dangerous heat threatens the region Tuesday.

A heat advisory was in effect through Wednesday in the Houston area and beyond, with temperatures expected to soar into the 90s (above 32.2 Celsius) and humidity that could make it feel as hot as 105 degrees (40.5 Celsius). The widespread loss of power, and therefore air conditioning, could make for dangerous conditions, the National Weather Service said.

More than 2.3 million homes and businesses around Houston lacked electricity Tuesday morning, down from a peak of over 2.7 million on Monday, according to PowerOutage.us.

“Houstonians need to know we’re working around the clock so you will be safe,” Houston Mayor John Whitmire said Monday, urging residents to also know the dangers of high water, to stay hydrated and to check on their neighbors.

Beryl has been blamed for at least seven deaths — one in Louisiana and six in Texas, officials said.

The storm weakened after making landfall, and late Tuesday morning it was a post-tropical cyclone centered over northeastern Arkansas, moving northeast with maximum sustained winds near 30 mph (48 kph), the weather service said. Its strength wasn’t expected to change much in the next two days.

The storm is forecast to bring heavy rains and possible flash flooding from the lower and mid-Mississippi Valley to the Great Lakes into Wednesday, the weather service said.

A flood watch was in effect for parts of Oklahoma, Arkansas, Missouri, Illinois, Indiana and Michigan. A few tornadoes were possible in Missouri, Tennessee, Kentucky, Illinois, Indiana and Ohio, forecasters said.

Beryl came ashore in Texas as a Category 1 hurricane, far less powerful than the behemoth that tore a deadly path through parts of Mexico and the Caribbean. But its winds and rains still knocked down hundreds of trees that had already been teetering in saturated earth and stranded dozens of cars on flooded roads.

It could take days to fully return power in Texas after Beryl toppled 10 transmission lines. Top priorities for power restoration include nursing homes and assisted living centers, said Texas Lt. Gov. Dan Patrick, who is acting as governor while Gov. Greg Abbott is out of the country.

Powerful storms in the area in May killed eight people, left nearly 1 million without power and flooded streets. Residents now without power after Beryl were doing their best.

“We haven’t really slept,” said Eva Costancio as she gazed at a large tree that had fallen across electric lines in the Houston suburb of Rosenberg. Costancio said she had already been without power for several hours and worried that food in her refrigerator would be spoiled.

“We are struggling to have food, and losing that food would be difficult,” she said.

The state was opening cooling centers, as well as food and water distribution centers, said Nim Kidd, chief of state emergency operations.

Beryl’s rains pounded Houston and other areas of the coast Monday, closing streets that had already been washed out by previous storms. Houston officials reported at least 25 water rescues by Monday afternoon, mostly for people with vehicles stuck in floodwaters.

Many streets and neighborhoods throughout Houston were littered with fallen branches and other debris. The buzz of chainsaws filled the air Monday afternoon as residents chopped up knocked-down trees and branches that had blocked streets and sidewalks. Several companies with refineries or industrial plants reported the power disruptions required the flaring of gases.

The earliest storm to develop into a Category 5 hurricane in the Atlantic, Beryl caused at least 11 deaths as it passed through the Caribbean on its way to Texas. In Jamaica, officials said Monday that island residents will have to contend with food shortages after Beryl destroyed over $6.4 million in crops and supporting infrastructure.