An incredible video shows needles of ice apparently flowing from a lake in Minnesota - even while the ambient air temperature is cool enough for passers-by to wear T-shirts.
The mysterious phenomenon at Medicine Lake, east Minneapolis, was spotted this weekend as winter temperatures finally broke in the state and the mercury soared to 26C.
Prior to that Minnesotans had just endured freezing weather that had led to the latest thaw of the state's frozen lakes since records began.
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Weird phenomenon: Passers-by reach out to touch the ice piling up on the shores of Medicine Lake, east Minneapolis, even as ambient temperatures are warm enough for them to wear T-shirts
'That's so cool': The mysterious-looking phenomenon was spotted as winter temperatures finally broke in Minnesota and temperatures soared to a balmy 26C
The video shows bemused locals wearing spring clothes and watching as ice seems to flow directly from the waters of the lake onto the land.
One woman among those watching can be heard exclaiming 'that's so cool' as needles of ice pile up against the shore in drifts.
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Local news weather reports claimed that the late end to winter had left Minneapolis's lakes still covered with a thin layer of ice which a south wind was pushing against their northern shores.
This was causing the ice to splinter and accumulate against the shore rather like snow, Minnesota's KARE11 news explained.
Ice drift: These scenes occurred at Medicine Lake in the west Minneapolis, but local weather reports suggested it was also happening at other lakes throughout the state
Thawing: The effect was caused by the thin sheets of ice remaining on the lakes crashing against the shore and splintering and accumulating at the edges rather like snow
'Like a really slow, really cold tsunami': The incredible video prompted a wave of comment on social news site Reddit
WHAT'S MAKING THE ICE PILE UP?
The video shows the effect caused by thin sheets of ice still covering the lake smashing into splinters as it its the shore.
Local weather reports explained that a stiff south wind was pushing the ice sheets against northern shores, causing them to splinter and accumulate like snow drifts of icy needles.
Some had speculated that it wasin fact needle ice growing rapidly from the soil, but weather conditions at the time do not support this hypothesis.
A video posted of the phenomenon on YouTube led to a wave of comment on social news website Reddit.
A user going by the name MedievalManagement quipped: 'Wow. That's like a really slow, really cold tsunami.'
Minnesota's weather, which fluctuates wildly according to season, remained cold and icy far later than usual this year.
It finally broke yesterday with highs of 27C in southern parts of the state, after earlier in the week temperatures had plumbed as low as 3C with snow.
Forecasters are, however, warning of more snow by Thursday.
Now watch a video of the incredible phenomenon
Ice appears alive as it is pushed against the shore at Medicine...
