Some comments from Andrew Hawkes:
Attached is a picture of the High Street in Jan 1979, taken about 10 am. Yes we did sell out of wellies because the snow was very wet and because there was a lot, it blocked the drains and the melting water could not escape. As soon as someone cleared the gratings, the water went.
Flooding: in my 60 years in the High Street I have not seen serious flooding, such as that hit Swanage. I have seen it where a drain has blocked and the water lies to a depth of 2 inches, flowing away down the next drain. In the past there has been a problem at the Railway Gate area. Again this is mostly down to blocked drains and a large puddle forms but usually you can walk round the edges.