As someone who experienced that winter I have noticed a couple of things
that reminded me of that March. I wonder if this spell had started with a
massive fall of snow what would have happened. For example I'm now looking
out of my window at yet another reasonable snow shower. That's 13
consecutive days now. This was quite common then, and in March it was
sometimes drizzly and fine snow. The ground was so frozen and with a foot of
frozen hard packed snow a slight thaw would have no effect. Some of the grey
murky days with temps around 1C were similar, but then they would have no
impact and the snow cover over the deep frozen snow.
It wouldn't have to have been much colder - ask the people on the Kent
coast!

Dave