Hints of Hurricane at Summit Station

Over the last 2 weeks we’ve had back to back wind storms with lots of drifting and blowing snow. On Wednesday, however, we got hit by the tail end of hurricane Nicole, by that time classified as a “post-tropical cyclone.” In a matter of hours our winds went from 20kn to over 60kn.

We follow similar weather criteria as the USAP: Condition 3 is visibility greater than 2000ft and wind-chill above -90F. Condition 2 is visibility between 2000ft and 200ft and/or wind-chill below -90F. And Condition 1 is the worst with visibility less than 200ft and/or wind-chill below -100F. When wind speeds exceed roughly 20knots snow is picked up reducing visibility and creating a white out. We’ve had a few cases of Con 2 recently with visibility under 2000ft, but I had yet to call on Con 1. Flag lines run between all the main buildings on station and during a storm all travel is monitored with radio calls including route and destination and check-in upon arrival. It can seem cumbersome at times, but it is also important to know where everyone is and that no one gets lost.

The day had started warm and a little windy with 20kn winds, but after midday they increased rapidly to 30kn then 40kn…finally hitting a peak sustained wind speed of 61kn gusting to 63kn! Unfortunately 53kn was the highest I saw on the station screen displaying current conditions.

Current Conditions: -4F and 53kn winds

That was by far the highest wind speeds I’ve seen up here, though I doubt it broke any records. Winter and early spring storms can be vicious on the ice sheet. The Big House, up on stilts, rocked as each gust buffeted the structure. At around 35kn we went into Con 1 and I made the call over the radio. I could no long see the Green House from the Big House. Travel was restricted to emergency or well-coordinated necessary activity with no solo travel permitted. Two people were in the Green House and went down to the SOB together to get the mechanic and bring him back. Visibility was down to just tens of feet and we ran a rope line along the flags between the Big House and Green House. Even in those high winds it was not hard to follow the flag line, but if something were to happen, if someone were to be blown over and injured or become disoriented, the consequences would be disastrous. So we are cautious and careful.

The storm was brief, however and winds died back down to 35kn pretty quickly. Overall the station fared well. A few large empty propane cylinders that are stored on the deck were blown over and there was significant drift growth around station. The buildings are far from perfectly sealed and we found several small drifts inside where ice and snow had been blown through a tiny crack. Walks around the berms revealed completely buried pallets in places and a few lighter items that had blown over, but not too much damage. We are prepared for potentially bigger storms through the winter.

Wind speeds off the chart!

Aurora Borealis

It’s a chilly evening in the heart of the ice sheet with temps hovering around -40F. We are outside, however, to witness a fantastic display of auroras! Tripods frost up, breath freezes on gaiters and hats, plastic becomes brittle, and above us the sky is alive.

I’ve written about auroras in a few previous posts here and here so I won’t go into too much detail, but a brief summary is that auroras are caused by energized particles from our sun striking gas molecules in the atmosphere (much like neon displays). The colors are due to which molecules are excited – green is caused by oxygen around 60 miles up while nitrogen causes the red-purple auroras. Solar storms and flares release waves of charged particles which can be predicted and tracked. To see the aurora forecasts and where they might be visible check out NOAA’s Space Weather page here: www.swpc.noaa.gov. NASA also has a fantastic page on Aurorae with photographs of aurorae on other planets!

The green line coming out of the far building in the last image is the CAPABL LiDAR I discussed in my previous post. The red light is the 50m tower.