The Little Ice Age: How Climate Made History 1300-1850 by Brian Fagan

Baltic and the English Channel. The same infiltrating creeks made the
surrounding low-lying coastlines vulnerable to unpredictable storm
surges, which would sweep up the narrow defiles and flood the land on
either side, forcing entire villages to evacuate or drowning them almost
without warning. We can imagine the scene, repeated so many times over
the generations. Huge waves of muddy water attacked the shore, spray
blowing horizontally in the dark mist masking the ground. The relentless
ocean cascaded up beaches and into narrow inlets, devouring everything
before it. Thatched farmhouses tumbled end-for-end in the waves; pigs
and cattle rolled like dice across inundated fields. Bedraggled families
clung to one another in trees or on rooftops until the boiling waters swept
them away. The only sound was the shrieking wind, which drowned out
everything-the growl of shifting gravel beaches, the desperate cries of
drowning victims, the groaning branches of tree lashed by the gale. When
the sky cleared, the sun shone on an enormous muddy lake as far as the
eye could see, a desolate landscape devoid of human life.

    No one could resist the onslaught of an angry North Sea, which contemptuously cast aside the crude earthen dikes of the day. The hydrological and technological know-how to erect truly permanent coastal fortifications did not yet exist. The first serious and lasting coast works date to
after 1500, but even they were usually inadequate in the face of savage
hundred-year storms. Small wonder the authorities often had trouble persuading peasants to settle on easily flooded lands.
    At least 100,000 people died along the Dutch and German coasts in
four fierce storm surges in about 1200, 1212-19, 1287, and 1362, in
long-forgotten disasters that rivaled the worst in modern-day
Bangladesh. The Zuider Zee in the northern Netherlands formed during the fourteenth century, when storms carved a huge inland sea from
prime farming land that was not reclaimed until this century. The
greatest fourteenth-century storm, that of January 1362, went down in
history as the Grote Mandrenke, the "Great Drowning of Men."3 A
fierce southwesterly gale swept across southern England and the English
Channel, then into the North Sea. Hurricane-force winds collapsed
church towers at Bury St. Edmunds and Norwich in East Anglia. Busy
ports at Ravenspur near Hull in Yorkshire and Dunwich on the Suffolk
shore suffered severe damage in the first of a series of catastrophes that eventually destroyed them. Huge waves swept ashore in the Low Countries. A contemporary chronicler reported that sixty parishes in the
Danish diocese of Slesvig were "swallowed by the salt sea." At least
25,000 people perished in this disaster, maybe many more: no one
made accurate estimates. The fourteenth century's increased storminess
and strong winds formed huge dunes along the present-day Dutch
coastline. Amsterdam harbor, already an important trading port, experienced continual problems with silting caused by strong winds cascading sand from a nearby dune into the entrance.

    In the early 1400s, more damaging storm surges attacked densely populated shorelines. On August 19, 1413, a great southerly storm at extreme low tide buried the small town of Forvie, near Aberdeen in northeastern Scotland, under a thirty-meter sand dune. More than 100,000
people are said to have died in the great storms of 1421 and 1446.
    Judging from North Atlantic Oscillation readings for later centuries,
the great storms of the fourteenth and fifteenth centuries were the result
of cycles of vigorous depressions that flowed across northwestern Europe
after years of more northerly passage when the NAO Index was low. The
changing signals of hydrogen isotopes from a two-hundred-meter section
of Greenland ice core GISP-2 tell us summer and winter temperatures for
the fourteenth century. This hundred-year period saw several wellmarked cycles of much colder conditions,