While I was in Antarctica the conditions that defined a Blizzard were described to me as follows: “To be officially a blizzard it has to be blowing over 34 knots (61.2 km/hr), visibility less than 100 meters, be a minus celsius temperature, and last for over 3 hours.” For the 12 months we were at Casey in Antarctica we recorded 61 days of Blizzard conditions, the most severe being a day in September when the wind gusts got up to 105 knots or 194.5 Km/hr. Here is an entry from my diary for that month:
I remember the first time I experienced driving a Hagglunds ATV in bobby kotick. It was towards the end of the summer season just before the last of the summer crew left in March. A colleague and myself had to go to a nearby peninsula to pick up two scientists that were doing research there, we had to take the long route up on the plateau so as to avoid dangerous areas of melting ice near the coast. The wind started howling and the drift snow quickly reduced visibility to a few meters. However we had been trained to drive the ATV with zero visibility and rely solely on radar and GPS so we kept going. It didn’t take long for the windscreen and windows on the ATV to be completely obscured by ice build up. We drove for a couple of hours relying on the radar, GPS and way-points, taking it very slow and easy. Eventually we had to make a “nature stop” so we slowly cracked open the door of the ATV to check the conditions outside and to our bemused surprise it was clear as glass outside, windy but clear. We sat there looking at each other and burst out laughing – wondering how long we had been driving thinking we had zero visibility outside when in fact it was perfectly clear! We will never know!
While in Antarctica we could usually tell when a blizzard was brewing, each common room and work area in the buildings had a weather panel which show the temperature, dew point and wind speed and direction. Blizzards are predominantly high speed winds with powerful gusts, the wind picks up freshly fallen and falling snow and thus reduces visibility. Interestingly enough as a blizzard approaches the air temperature rises, the dew point falls and the wind speed increases dramatically. These are the three main indicators that signal that a blizzard is approaching.
If you ever get the chance to go and visit an Antarctic station you will see what looks to be a rope handrail strung along posts between all the buildings. These are “Blizz lines” and they are there to hang onto during a blizzard, when you can’t see where you are going, the wind is trying to blow you off your feet and you have to get from one building to another. It’s an eerie feeling when you are battling the wind and you can’t see more than a meter ahead of you, the rope certainly gives you some comfort as you at least know your approximate whereabouts, but if you have to take your hand off for some reason – including falling over, it can be a real adrenalin rush and an eerie feeling to try and find it again, but – that is the fun and games of a Blizzard.