air temperatures of 12 �F (?11 �C) were accompanied by 30 to 48 miles per hour (48 to 77 km/h) winds. Wind chill equivalents reached ?10 �F (?23 �C) according to NOAA. Several days into this pattern, local ponds and smaller lakes freeze solidly enough to allow skating. Outflow winds can collide with a Gulf of Alaska moisture and create ice, snow, or heavy rains. This transition can also lead to freezing rain, referred to as a "Silver Thaw" that produces hazardous driving among other inconveniences.
Another weather phenomenon, known as the "Pineapple Express", happens in the autumn. For most of a day, an unusually warm and steady wind comes out of the south. It is essentially a reverse northeaster. (Some film of a northeaster and a "Chinook" can be seen at this link:.) A variation that occurs in winter following several days of northeast outflow winds described above can melt significant snow accumulations very quickly, pushing drainage systems to their limits
