Over 939,000 Customers Without Power in Texas, Other States From Storms

Wreckage is strewn across a property the day after a deadly series of tornados hit the central United States, in Valley View, Texas, U.S. in a still image from aerial video. ABC Affiliate WFAA via REUTERS/ File Photo Purchase Licensing Rights

That is up from around 754,000 customer outages earlier on Tuesday.

Tornado-spawning thunderstorms that swept the Southern Plains and the Ozark Mountains killed at least 21 people across four U.S. states over the long Memorial Day weekend.

Texas power company Oncor, a unit of California-based energy company Sempra Energy (SRE.N), opens new tab, has the most outages with over 591,000 customers without power in the Dallas-Fort Worth area, according to PowerOutage.us.

Oncor said it was "currently monitoring and responding to outages caused by thunderstorms producing large hail and wind gusts up 80 miles per hour (129-kilometers per hour) in the Dallas-Fort Worth area and surrounding areas."

With the storms still battering the region, Oncor said it was not yet able to estimate restoration times for many customers.

Major outages by state: