Snow, icy wind and plummeting temperatures have prompted an unprecedented surge in demand for home heating oil from householders - with delivery lead times now sitting at over a week.
Prices have also risen, according to the NI Consumer Council, with the average cost of 900 litres sitting at £455.55 yesterday compared to £430.30 on February 15 - a hike of £25.25 in just a fortnight.
Homes in Belfast, Bangor, Newtownards, Dundonald and Donaghadee have been contacting Bangor Fuels in their droves and the company is currently making more than 500 deliveries a day.
"It's much busier than it normally is at this time of year," employee Darren said.
"We usually make 300 daily deliveries but now it's more than 500. We can normally offer a next-day service but we're backed up until next Thursday.
"A lot of people have been caught completely unawares by the bad weather and around 75% of the calls we've taken have been from people who've ran out of fuel.
"We act on a first come, first served basis so we'd advise householders not to leave it until the last minute until they place an order."
Patterson Oil, which serves Belfast, Bellaghy, Gilford and Omagh, said its phones have been ringing off the hook as the weather gets set to worsen over the weekend.
"The demand is coming from right across the province," a spokeswoman said.
"It's an awful lot busier than normal at this time of year and we are fulfilling orders as soon as possible but the lead times are longer than normal." Oil delivery companies in Londonderry have also reported a record hike in calls from customers for last-minute supplies.
Thomas McGlinchey from Springtown Fuels said he has had seven oil delivery lorries on the road servicing customers in Derry and Strabane.
He added: "Each lorry carries 14,000 litres and they're on the road all day. It's gone mental and it hasn't stopped since last Saturday; we've been flat out trying to get the lorries out to homes."
Meanwhile, David Blevings of the Northern Ireland Oil Federation said its members would continue to cope with a sudden demand which, he added, was unprecedented.
"Oil deliveries are continuing as normally as possible. Our members are presently under pressure but they will cope with that," he said.
"Some customers will have to wait up to a day or two before their deliveries are made and we are sure they understand the situation. Like any logistical operation the sector must forecast for demand and at the moment we are seeing an unprecedented demand and we are dealing with that."