Claims for flood damage will cost more than £20 million in Cumbria alone, insurers have estimated.
NFU Mutual launched its emergency claims plan to speed help to its policyholders and is already dealing with more than 200 flood claims.
It is making emergency payments of £500 - or more if necessary - and arranging emergency accommodation for people who are unable to stay in their homes.
It came as Forage Aid chiefs mobilised teams to the worst hit areas and issued a plea for donations.
NFU Mutual chief claims manager, Matthew Scott, said: “Our network of local agents across the north of England is telling us that events in Cumbria are on the scale of the 2005 floods; with the potential to be even worse.
"The flood waters are more widespread than in the 2005 and 2009 floods so we anticipate that more homes, farms and businesses may be affected than in the previous floods.
“However, we have had reports that some of the worst-hit areas in the earlier floods have not suffered such severe damage this time.
"We have activated our emergency plan and our network of local agents is working hard to support their communities.”
While Cumbria is the worst-affected part of the UK, the weekend’s floods and storms have also caused damage to homes and businesses across the north of England, southern Scotland, Northern Ireland and North Wales.
Now the flood waters have dispersed, communities are faced with a major clean-up operation.
As news of the crisis broke, the farming community quickly sprang into action and began pledging fodder and bedding.
Auction marts around Cumbria have agreed to act as storage and unloading sites.
Lincolnshire arable farmer and Forage Aid founder Andrew Ward praised the farming community’s response.
“This is the third extreme weather event I have been involved in and the generosity shown by the farming community still never ceases to amaze me. The amount of support people have shown has been absolutely staggering,” he said.
Mr Ward urged anyone wanting to make donations should do so via the Forage Aid website. Anyone needing aid should also register their details on the website.
He added: “We are operating closely with Farming Community Network (FCN) RABI and NFU Cumbria.
“Anyone who needs help will receive a visit from one of the representatives before anything is sent out.
“We are also asking for anyone to come forward who may be able to offer grazing outside the affected areas.”
During a flood
Remember that personal safety is your prime concern. Don’t go into rooms with standing water if the power is still on, and don’t use electrical appliances affected by, or in contact with, moisture
Don’t take unnecessary risks to save possessions
After a flood
Do not drink tap water until the all-clear is given
Your electrical system needs to be checked and safety confirmed before turning back on
Take photographs of damaged items - you can use a mobile phone camera - as this can help with the claim