You better be ready when a giant wave comes crashing down - not just in the ocean - but also the atmosphere.

Atmospheric wave pattern (reconstructed using modern data) that set up the 11/11/1911 “Great Blue Norther”. A huge dip in the jet stream over the western half of the country and big ridge (rise) over the East set up a volatile transition zone in the heartland. (NOAA (via University of Missouri) )

The Chicago Weather Center offers some more background:

One of the most sudden and dangerous cold blasts in American history roared across the Plains and Midwest one hundred years ago today, November 11th 1911. In addition to the historic temperature drop, the storm system known as “The Great Blue Norther” also produced deadly tornadoes that were quickly followed by blizzard conditions.

The incredible blast of cold air arrived on the leading edge of a huge dip in the jet stream, the stormy segment of a long wave in the atmosphere.

“...the cold air mass interacted with a strong jet stream that then uncharacteristically plunged south to the American Midwest and into an existing and unusual warm and moist air mass being funneled into the Midwest by southerly winds from the Gulf of Mexico” according to researchers at the University of Missouri (UM).

In the days before satellite or radar, these researchers found residents had little warning. That was surely the case in Janesville, Wisconsin, where an F4 tornado killed 9 people and injured 50, according to the National Weather Service (NWS).

“Within an hour after that tornado struck, survivors were working in blizzard conditions with near zero degree temperatures to rescue people trapped in tornado damage debris,” the NWS wrote.

Patrick Market, an atmospheric scientist at UM, described the Blue Norther as a “rare and unique” event. The closest analog to this storm is one that occurred on January 29, 2008, but wasn’t nearly as strong according to Market and his team.

Related: Interactive map showing observations in Missouri on November 11, 1911


On the subject of big waves and rare events, the world record for largest ocean wave ever surfed, 90 feet high, was set Tuesday just offshore Portugal. Wunderground meteorologist Jeff Masters describes the atmospheric setup: approaching cold front extending southwards from a low pressure system centered just south of Iceland generated strong winds off the coast of Portugal, and a west-northwest swell of 8 meters (26’). The canyon generated three big waves in excess of 60 feet that day, and McNamara was able to catch the tallest, 90-foot wave.

Here’s the video...

Fortunately, unlike Midwest residents in November 1911, Hawaiian surfer Garrett McNamara was ready for the ride.