reply to post by rogerstigers
As others have said, it's a combination of factors. From my perspective here in Central Europe, there are a few key variables that determine if
there'll be flooding during or after the snow melts:
-- average amounts of snow but rapid temp increase in spring: this can cause the snow to melt faster than most of the water can be absorbed by the
-- average amounts of snow but a rainy spring: if we get above-average rainfall during the melt season then flooding is a distinct possibility. The
rain itself hastens the melt and seriously increases runoff into catchment areas.
-- above-average snow and normal to above-average temperatures in spring, combined with plenty of rain: a very serious situation and almost guaranteed
to cause serious flooding.
When analysis by our hydrology experts shows that the conditions for a spring-melt flood are likely, the flood gates at the dams are opened to lower
reservoir levels. This often helps to reduce the flooding effects, but has negative impacts on locations down-river from us (mainly Germany).
This winter, it's way too early to say if we're facing a potential spring melt flood. Yes, we've had a fair amount of snow but we've had more in the
past with no serious effects. And other times, we've had less snow but been hit by floods due to an extremely rapid melt combined with a very rainy
Statistically, while January/February give us the most precipitation, our wettest
months are in summer. In fact, the Czech's worst flood in the
past 500 years occurred in the summer of 2002. The 2001/2002 winter was around normal but as the snow melt had already saturated the ground in spring,
when heavy rains hit in August most of the water ran off and the floods were very extensive and devastating.
So, it's not just the snow melt that we have to be concerned about, but its possible influence even months later.
edit on 24/12/10 by JustMike because: I missed a bit.