Snow, Global Warming and Flooding

Over the past few days I had several people ask me whether the cold, snowy weather of the past several weeks indicates that global warming is either a fallacy or being stopped by lack of sunspots or some other cause. The answer is our cold spell has absolutely nothing to do with global warming. The "Global" in global warming is the key. The earth is going to warm up due to increasing greenhouse gases like CO2 and methane (and indirectly from increases in water vapor). But not every location will warm up the same amount or at the same rate--with the polar regions warming up the most, the continents more than the oceans, and the eastern oceans less than than the western oceans. We are downstream of the Pacific (an eastern ocean), which controls our weather. So the Pacific Northwest may well be a location where global warming is delayed. Our computer models suggest we will get very significant warming..but not until the second half of the century.
It is also important to note the atmosphere has quite a bit of local and short-period natural variability, which can produce short periods of cooling in a region, even if global warming is occurring.

My second point is about the upcoming heavy rains in the mountain and major warming. The high resolution WRF atmospheric model we run in the department (which I show you quite frequently) indicates the potential for 10-20 inches of rain over the next two days on the windward mountain slopes. We also couple the high resolution weather prediction models and hydrological models of stream flow. The results of the latest simulations are scary, with major flooding on several rivers. In addition to the rains there could be substantial melting of the low-elevation snow pack. More on this tomorrow.