Geoscience Reference
In-Depth Information
979 hPa
971
986
18:00
Jan 30
966
12:00
Jan 31
Aberdeen
966
North Sea
4
Heligoland
970
975
3
Zuider Zee
The
Wash
979
6:00
Feb 1
2
England
The Netherlands
1
1) English Channel -1703
2) Zuider Zee -1287
3) N. Frisian Is. -1362
4) Jutland, Denmark -1825
Location of some historical, erosive North Sea storms including the path of the 1 February 1953 storm.
Fig. 3.13
1362, parts of the North Sea coast of Schleswig-
Holstein eroded 15 km landward, turning a low-lying
estuarine coastline into one bordered by irregular
barrier islands separated from the mainland by lagoons
5-10 km wide. Over 60 parishes, accounting for half
the agricultural income in this area, were destroyed.
Storms in 1634 severely eroded both the Danish and
German coasts and, in 1825, a North Sea storm sepa-
rated part of the northern tip of Denmark from the
mainland, leaving behind several islands. These storms
also directed the course of history. In 1588, the Spanish
Armada of 130 ships, after being forced into the North
Sea by marauding attacks from the outnumbered
British fleet, was all but rendered ineffective by a five-
day storm off the east coast of Scotland (Figure 3.14).
What remained of the Armada was finished off by
more of these storms as the fleet tried to escape west
around Ireland. The summer of 1588 was character-
ized by an exceptional number of cyclonic depressions,
corresponding to a polar jet stream diverted much
further south and wind speeds much stronger than
could be expected at present.
None of the extra-tropical storms mentioned above
have been matched in the twentieth century for loss of
life. However, there have been big storms. Most
noteworthy was the North Sea storm of 1 February
1953. This storm developed as a low depression north
of Scotland and then proceeded to sweep directly
south-east across the North Sea (Figure 3.13). The
lowest pressure recorded was 966 hPa. While this is
not as low as pressures produced by tropical cyclones
(see Table 3.1), it represents an extreme low pressure
for a cold-core depression. Wind speeds at Aberdeen,
200 km from the center of the storm, exceeded
200 km hr
-1
. These velocities are similar to those
experienced in tropical cyclones. Tides in the North
Sea were superimposed upon a seiching wave (also
known as a Kelvin wave) that moved counterclockwise
along the coast because of Coriolis force. The storm
moved in the same direction as this Kelvin wave. In
doing so, it set up a storm surge, exceeding 4 m in
height, which flooded The Wash in England and
breached the dams fronting the Zuider Zee. (The
effect of this surge will be discussed in more detail at
the end of this chapter.) In Britain, 307 people died,
32 000 inhabitants had to be evacuated, and 24 000
homes were damaged. Over 83 000 hectares of
valuable agricultural land were submerged under salt
