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:
"Apart from a few mild days, the rest have been a strange mixture of howling wind from all directions, blizzards lasting for day's and snow storms reducing visibility to less than a meter. On Thursday the 11th a top wind speed of 105 knots (194 km / h) was recorded, only half an hour before that, there was a whirling snow storm with only mild winds from all directions. I took the opportunity to go across the road to the store to get some work gear, when I was about to leave the wind changed and started howling from the east, bringing with it a thick snow drift, I attempted to get back to the accommodation building but had to turn back as I couldn't see my feet in front of me, after a couple of attempts I decided to wait until it calmed a little. Eventually after the visibility improved markedly I leapt out, head down with the wind at my back, as soon as I stepped out a gust of wind caught me and I went ass up into the snow, I got up and bee lined for the building, I was thrown over twice Before I reached a vehicle parked outside, I grabbed onto the tray to stop from being thrown into the stair case at the entry porch, when I got inside I checked the wind speed display, it was gusting at 102 knots. A fellow colleague at around the same time was coming back from the Science building, with the wind at his face. There is a small concrete bridge on the road just before the Science building, he reported that he had to cross it several times as the wind kept blowing him back across it's smooth icy concrete surface, he eventually crossed it on his hands and knees.
I remember the first time I experienced driving a Hagglunds ATV in Blizzard conditions. 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.