Tsunamis in the Alps? A killer wave slammed medieval Geneva, a new study says... [500 A.D.]

National Geographic ^ | Wednesday, October 31, 2012 | Daniel Stone

[SunkenCiv]

Nearly 1,500 years ago a massive flood in Geneva reportedly swept away everything in its path -- mills, houses, cattle, even entire churches.

Now researchers believe they've found the unlikely sounding culprit: a tsunami-like killer wave in the Alps. The threat, they add, may still be very much alive. (Video: Tsunamis 101.)

Spurred by a huge landslide, the medieval Lake Geneva "tsunami" (technically defined as a seismic ocean wave) swamped the city, which was already a trading hub, according to a new study.

Far from any ocean, the massive wave was likely generated by a massive landslide into the Rhone River, which feeds and flows through Lake Geneva, according to a group of Swiss researchers.

The team analyzed a massive sediment deposit at the bottom of the lake's easternmost corner and determined that the material had once sat above the lake and had slid all at once into the Rhone, near where the river flows into the eastern end of Lake Geneva (map).

The sudden splash sent a tsunami barreling down the length of the 225-square-mile (580-square-kilometer) lake toward Geneva, at the western end of the lake, the study suggests. Researchers estimate the wave was between 9 and 26 feet (3 and 8 meters) tall, depending on how quickly the rockfall occurred, which they were unable to measure.

[cripplecreek]

And they'll kill you in a hot second if you give them half a chance.





Just about every pier and breakwater along lakes Michigan and Superior have memorials to people who died after being swept off them. A Coast Guard officer at Grand Marais Michigan told me they always die in 3s. Usually two mistaken teen immortals and one older man who can't bear to watch them die.

[SunkenCiv]

Because the water is fresh, it comes in something like 7/6ths faster, meaning that a series of waves will take a vessel apart faster on the Lakes than on the oceans and seas (everything else being equal of course).

Years ago I saw a family from south of the border somewhere walk toward the waterline in Grand Haven, staring at the water out to the horizon, and the dad put his hand down, cupped up some, tasted it, and said, basically, it isn’t salty. Foreign visitors are sometimes amazed. It’s weird to think that I take it all for granted — doesn’t everyone have something like this within an easy drive of their homes? :’)

I’ve often enjoyed swimming in wave conditions which probably weren’t safe, but I *always always always* avoid swimming by the piers. Besides unseen crap below the surface that can hook you, knock you cold, etc, the currents are much, much worse. Natural undertow is nothing by comparison.

The Edmund Fitzgerald had been the largest vessel ever on the Lakes, and nothing surpassed it for decades, probably due to economic factors.

[cripplecreek]

I always liked this video.

A Gale on Lake Superior December 29th. 1993 aboard the Charles Wilson

[colorado tanker]

Roman Geneva was originally founded as a border town to protect Gaul against the Helvetii. After the fall of the Empire it was absorbed into the Burgundian kingdom.

[SunkenCiv]

Thanks ct.

[Mr Radical]

sorry, but the innocent Swiss milkgirl is to be played by Michelle Obama.

[MadMax, the Grinning Reaper]

let’s just say that the innocent Swiss milkgirl has her own pair of Alps. Michele - more like sand-dunes. Bad casting.

I hear that Stormy Daniels is available for the part.