The Environment Agency now estimates that about 900 properties were damaged in the upper Calder Valley floods on Friday.
The bill for repairs and clearing-up operations could run into tens of millions of pounds.
Council and Environment Agency workers are continuing to help householders, shop keepers and businesses to clear up and investigate the causes of what is being described as a once in 60 years event.
They are pulling together information from many different sources to improve their systems and responses.
Craig McGarvey, the Agency’s Yorkshire area manager, said: “We have seen at first hand the devastating impact of flooding, and our thoughts are with those whose homes and businesses have been flooded.
“At one point the River Calder rose by two feet in fifteen minutes, with many days of rain falling in six hours and water running off the hills rapidly.
“Our flood ambassadors are out this week in the flooded communities giving advice and guidance on what to do after a flood, and gathering information on possible improvements to our warning and informing arrangements.”
About 400 Todmorden properties were affected by flooding from Walsden Water.
The gate to the Centre Vale Park the flood storage area for the town, was activated by remote control from the Environment Agency’s Leeds office around 8.30pm on Friday, before its normal trigger level of two metres. This helped disperse some of the surface water.
The Environment Agency is investing £30 million in providing flood protection to Todmorden and Walsden, in a three phase project. Phases one and two are complete, with protection for around 230 properties.
Phase three has begun and is expected to be completed in summer 2013. Once complete, a total of 858 properties will be better protected.
The first Flood Alert was issued for the Upper Calder was at 10.31am on Friday and sirens in Todmorden were sounded at 7.55pm.
“We issued Flood Warnings direct to 585 properties in Todmorden and Walsden. Flood sirens were used from 7.55pm on Friday evening. Flood Warnings were issued at 8.10, 8.40 and 9.40pm. The catchment is very quick to respond, and we have worked with the community to help them understand their flood risk.”
Calderdale flood facts:
Hebden Bridge, Todmorden and Mytholmroyd are in the rapid response Upper Calder catchment. Heavy rainfall fell on Friday 22 June on to already saturated catchments, with up to 50mm falling in 12 hours.
Hebden Bridge recorded its highest ever river level at 3.311m, some 0.285m higher than June 2000.
Flood warnings were issued to 177 properties in Hebden Bridge, 52 properties in the area are not signed up to receive our flood warning.
Floodline Warnings Direct is a free service which sends you a direct message when flooding is expected and may affect your property. You can receive warnings by telephone, mobile, email, SMS text message or fax. To find out if your property is at risk of flooding and if you are eligible for Floodline Warnings Direct, call Floodline on 0845 988 1188 or visit our website at www.environment-agency.gov.uk/flood