The weather can get dangerous in Antarctica very quickly. Lack of visibility and extreme cold can lead to serious injury. In order to prevent this, McMurdo has a system in place to stop people from venturing outside when the weather is dangerous. The weather conditions are classified as condition 3, condition 2, and condition 1.
Condition 3 is “normal”. It means that the weather is nice enough that there are no restrictions on travel between buildings and activities. The official definition (according to the USAP website) is winds less than 48 knots, visibility greater than or equal to ¼ mile, and wind chill temperature warmer than -75°F.
Condition 2 means that the weather is worse, but passable. All recreational travel is prohibited, and you’re only allowed to walk between buildings. You’re only allowed to drive somewhere in a radio equipped, enclosed vehicle and you have to check out with the central communications office so that they know where you’re going. According to the USAP website, the official definition is winds 48 to 55 knots sustained for one minute, visibility less than ¼ mile, but greater than or equal to 100 feet sustained for one minute, or wind chill -75°F to -100°F sustained for one minute. Once any of those requirements is met, the station changes to condition 2.
Finally, condition 1 means that the weather is severe, and everybody must stay in the building they’re in or get inside the nearest shelter. You’re not even allowed to walk between buildings directly adjacent to each other. It can be seriously dangerous to be outside in a condition 1 storm. The official USAP definition is winds greater than 55 knots sustained for one minute, visibility less than 100 feet sustained for one minute, or wind chill greater than -100°F sustained for one minute. Again, if any of these requirements are met, the station changes to condition 1.
Condition 1 is an uncommon occurrence, it almost never happens during the summer season and happens rarely even in winter. It completely shuts down the station and no one is able to work (including us). The lidars obviously can’t operate in a storm, but usually we can’t even make it to the lab to work on maintenance or other projects. We had our first condition 1 storm of the season yesterday. While it’s unfortunate that we’re not able to get to the lab or collect data (especially because data during the stormy season is very valuable), seeing a condition 1 storm is a rare opportunity to see the raw power of this continent.
Left: Condition 1 during the daytime. This photo was taken around 9 am on 10/14/25, during a condition 1 storm that swept through shortly after I arrived at McMurdo. The view is from a window on the second story of building 155.
Right: Condition 1 during the nighttime. This photo was taken around 6 am yesterday (5/25/26), during the most recent storm. The view is from a doorway of building 207.
Unfortunately the storms cannot be fully captured without videos, which show the snow whipping by in powerful winds. Sometimes visibility can drop down to just a few feet.
