A Blizzard is a severe snowstorm. They have high winds and low visibility.
History
Major Louis Ferretti once described going through the Stargate to Captain Samantha Carter as being "frozen stiff, like you've just been through a blizzard, naked." Carter explained that it was the result of the compression the traveler's molecules undergo during the millisecond required for reconstitution. (SG1: "Children of the Gods")
When the touchstone was stolen from the planet Madrona by the Rogue NID in 1998, the Madronans experienced a blizzard with wind speeds that were up to 80 miles an hour. Captain Carter warned that if it got worse, the whole planet would be a write-off. However, SG-1 managed to return the device in time and Sam reported that everything should go back to normal on Mardona and Earth within a few weeks. (SG1: "Touchstone")
In 2000, Major Michael Griff and his team, SG-2, searched for SG-1 on P3R-118 while in a blizzard. (SG1: "Beneath the Surface")
The Destiny expedition encountered an ice planet that had blizzard weather conditions. (SGU: "Water")