A lightning strike may have caused a power cut which left more than 63,000 homes without electricity.
A Lancashire Fire and Rescue spokesman said lightning hit the electricity substation on Caton Road in Lancaster on Wednesday morning.
But Electricity North West said it was “too early to say” what caused the power cut which affected Lancaster, Morecambe and Carnforth.
Properties across the area reported electricity supply problems from around 11.45am.
Firefighters had to rescue people trapped in a lift on Market Street in Lancaster and on King Street in Lancaster as the power went off.
Fire engines were also called out as alarms went off across the district.
Some premises were back on by 12.30pm.
But Forton services on the M6 was still closed in both directions on Wednesday afternoon due to the power cut.
Traffic lights were also still out near Aldi on Morecambe Road just after 3pm.
The Dukes Theatre in Lancaster tweeted on Wednesday afternoon that their power was still off and staff were offering ice creams to passersby. They later said power had been restored.
British Transport Police said the power cut was affecting Lancaster railway station with lifts and information screens out of action.
Trains and signals however, were not affected and continued to run.
At 2.30pm on Wednesday, Electricity North West said it had restored power to 53,000 of the affected premises and was still working to get the other 10,000 back on.
They said engineers were on site within a few minutes and restored power to around 12,000 customers within half an hour and a further 30,000 within the first hour.
By 4.30pm, they said all power was back on.
Electricity North West control room manager, Sam Loukes said: “Our engineers were quickly at the site to determine the issue and start restoring supplies.
“It’s too early to say exactly what has caused the power cut, although we are aware of some bad weather in the area earlier.
“Our focus is now on restoring power to the final properties affected and ensuring that the power stays on.”
The Met Office had issued a severe weather warning for Wednesday and Thursday in the Lancaster district with lightning expected in the evening. But although there was heavy rain on Wednesday morning, residents in Lancaster said they had seen no lightning immediately before the power went off.
The last major power cut in our area came in December 2015 when Storm Desmond caused the Caton Road substation to be flooded.
Around 55,000 properties were affected at the time, some losing power for 56 hours.