With only three claims days until Christmas, insurers, loss adjusters and disaster recovery companies are all bracing themselves for more heavy rain, high winds and gales over the holiday season. The long-range weather forecast is not for the usual seasonal frost which gives us a rash of burst pipes over the Christmas period, but for more flooding.

CGNU is already talking of its bill for the recent floods being at £200m and Royal & Sunalliance put its estimate at £100m. And that was before the waters had subsided and the work of drying out and reinstatement could begin. We believe that for homes which have been heavily saturated the whole process can take up to six months. Many families who have seen their homes flooded once this year, may well see them flooded again over the Christmas period. This will mean the clock having to be put back and the whole drying process started from scratch.

Not that flooding at Christmas is a rarity. Last year with the longer millennium holiday we experienced three times as many flood related call-outs as normal. It has to be said that something like Murphy's Law of weather seems to operate on British bank holidays – whatever bad weather is around, will usually strike on a bank holiday.

What has made the recent floods and those we expect over Christmas so expensive and depressing is the fact that because the water takes so long to drain away, it sits in the properties for days and sometimes weeks before drying out and repair can begin. If we can get to a dwelling within a few hours of the flood then the final cost can be reduced by as much as 90%. Within 12 hours costs can be reduced by 70% and within 24 hours costs can be halved. However, such has been the severity and the persistence of the recent floods that we have not been able to get into many properties for several days. The damage is so bad that even the insulation material between walls has been affected. In more normal circumstances we calculate that reinstatement can take place after approximately six weeks of drying out.

The Christmas festivities also generate their own odd claims. There are the party goers who fall asleep in the bath. One such case last year not only ruined the bathroom but ruined the flat underneath and with it five people's Christmas. The costs worked out at over £10,000. There was also the family who went to the pub and while they were out the turkey caught fire and the whole house was smoke-damaged. Then there was the fish tank which burst on Christmas Eve and spilled 50 gallons of very smelly water all over the presents which were waiting for the next day. We think the tank had been knocked over by one of the children trying to get a sneak preview of Santa's offerings.

Traditionally, we get more claims at weekends because those are the days when appliances are used most often and therefore accidents with washing and dishwashing machines – not to mention water tanks – are most likely. Most years these everyday claims outscore those from river flooding, though this year may be the exception. In previous years, even when there has been a lot of flooding, it only accounted for one in five of our calls.

Despite Murphy's Law, however, bank holidays usually see a drop in claims. This is because fewer people use their appliances, and if something does happen, they are at home and can nip any disaster in the bud. Many people also feel that over the holiday there is little point in calling their insurance company – they wait until after the break. There are also those who have been away and come home to find a flood.This helps explain why we always see a rise in claims after a holiday. This means that if the long-range weather forecast is wrong and there are no floods during the holiday, claims for the four day Christmas holiday could be as much as two thirds down on those for a normal period.

But who dares bet against bad weather on a bank holiday? It is easy to forget that before the end of October this had been a relatively flood-free year. But we are certainly not leaving anything to chance and, as on other holiday periods, this Christmas we will be providing our usual service throughout the UK.