1 million customers are without power in Texas, and it could be a ...

Nearly one million customers in Texas are without power Tuesday as powerful storms delivered another round of violent weather to the state still reeling from an almost unrelenting parade of destructive and deadly storms in recent weeks.

Storms unloaded hurricane-force wind gusts across the Dallas area, with Dallas Fort Worth International Airport recording a wind gust of 77 mph early Tuesday as power outages in the area started to skyrocket.

The same damaging storms that tore through Dallas then hit Houston with hurricane-force winds Tuesday afternoon. Houston’s George Bush Intercontinental Airport recorded a wind gust of 75 mph.

Videos captured across Dallas and Houston communities revealed scenes of disaster and flooding Tuesday. Footage from north Dallas obtained by CNN showed multiple cars stranded in a flooded roadway, surrounded by frequent lightning as the rain continued. In other communities, powerful winds ripped out trees and forced them onto homes and knocked down neighborhood fences, leaving communities in disarray.

The power outages started to ramp up early Tuesday morning in the Dallas area, then extended south with the storms as they roared across the state, according to PowerOutage.us. Hundreds of thousands of outages were in Dallas County, where officials issued a disaster declaration and warned outages could last for days.

READ: White House announcing action to modernize electric grid and pave the way for fewer outages

These storms have arrived even as some residents are still mourning at least seven people killedin the state during violent storms over Memorial Day weekend. In total, almost two dozen people, including four children, were killed across five states as storms hit the central US over the holiday period, and several communities are grappling with significant losses of homes and businesses.

Parts of Texas and extreme western Louisiana face Tuesday’s most serious threat of severe weather. Large hail, lightning and wind gusts as strong as 80 mph are the main threats with any storm. A few tornadoes may also occur, according to the National Weather Service.

Some of the same areas rocked by storms early Tuesday could encounter more storms Tuesday night as another round fires up late in the afternoon in western Texas and Oklahoma and tracks east.

Already, the weather has spelled misery for hundreds of travelers. More than 600 flights flying in and out of the Dallas Fort Worth International Airport and the Dallas Love Field Airport have been canceled – and more than 900 flights in and out of the two airports have been delayed, according to FlightAware data.

More than 75 flights in and out of Houston’s William P. Hobby Airport and George Bush Intercontinental Airport have been canceled, while more than 530 have been delayed.

Sunday was the busiest severe weather day of the year so far, with more than 600 reports of strong winds or hail across more than 20 states, including gusts over 75 mph and hail the size of softballs. Twenty-six tornado reports also were made in 10 states. Storms turned homes and businesses into piles of rubble, flung cars and brought down power lines.

Power outages could last days in Dallas

It could take days to fully restore power in the Dallas-Fort Worth area after violent storms unleashed hurricane-force wind gusts Tuesday morning. Dallas is the second major Texas city to have critical power infrastructure damaged by severe weather in less than two weeks.

“This, unfortunately, will be a multi-day power outage situation, similar to the one that (occurred) in Harris County and Houston,” Dallas County Judge Clay Jenkins cautioned during a news conference Tuesday.

A derecho and tornado in mid-May blasted 100 mph wind gusts through the Houston metro, killing multiple people and knocking out power for days.

The full extent of damage to power infrastructure in the Dallas area is still being assessed, but the current prognosis is concerning, according to Grant Cruise, a spokesperson for Oncor — the state’s largest utility company.

“We did have a significant number of downed lines because of this weather event,” Cruise said during Tuesday’s news conference. “In many cases it’s not going to be simple repairs, we’re looking at complete reconstruction for parts of our area.”

The storm damage prompted Jenkins to issue a disaster declaration for Dallas County.

The outages come as some Texans head to the polls Tuesday for primary runoff elections. More than a third of Dallas County’s polling places were without power Tuesday afternoon, according to Jenkins.

Summerlike heat will ease in Texas this week, but those left without power or a reliable way to cool down could still face the risk of dangerous heat stroke or heat exhaustion.

CNN’s Andy Rose contributed to this report.