Nearly 40,000 utility customers in Alabama remain without power on Saturday following a powerful weather system that spawned two tornadoes and left three people dead on Friday.

About half of those outages involve Alabama Power customers, including over 50 power outages affecting hundreds of customers in the Birmingham metropolitan area.

In Florence, the city’s electricity department is alerting residents to be patient, calling the power restoration a “multi-day event.” According to a social media post on Saturday, crews were still working to restore power to over 7,000 customers. Crews from Opelika Power Services and Russellville Electric have joined the utility. The utility is tracking the power outages online.

Cullman Electric Cooperative is working to restore power to 8,000 customers who remain in the dark on Saturday. According to an 8 a.m. Facebook update, approximately 1,000 customers had power restored overnight. The utility, in its social media update, warned customers that “due to a large number of individual outages, many areas will not have power restored until sometime this weekend.”

The Alabama Rural Electric Association, in a morning post, said a number of small electric cooperatives were planning to assist fellow co-ops Joe Wheeler EMC and Tombigbee Cooperative, where power outages remained Saturday. The Tombigbee Cooperative, in northwest Alabama, has about 3,600 power outages remaining, according to the poweroutage.us map. That’s about 40% of its customers.

Huntsville Utilities is reporting, as of 9:10 a.m., that 2,532 customers remain without power, 66 lines were down, 19 poles remain downed and 20 poles are damaged but not downed. The utility, in its Facebook post, said it does not have restoration estimates for specific areas.

The North Alabama Electric Cooperative is reporting approximately 400 outages remaining among its customers, down from over 2,000 after the storm hit on Friday. Athens Utilities, in an update this morning, reported that power had been restored to all but 1,200 customers, down from 6,800 outages Friday afternoon.

The powerful storm system is blamed for spouting heavy winds and two confirmed tornadoes in north Alabama. The three fatalities, according to The Associated Press, occurred in Talledega County, Lauderdale County and in Huntsville. All three occurred from fallen trees.