Why is it snowing in LA?

Answer 1

The basic of physics is that a cold front pushed its way down from the arctic and caused the surface temperature in the Los Angeles area to drop. Generally due to its latitude and the movement of the currents, LA is nearly always warm, so you get rain if you get percipitation. However, during the recent cold snap, as moisture accumulates, the water forms frozen percipitation and fails to melt by the time it hits the ground, causing snow.

Okay, so that was a really literal answer... I'm sure what you wanted to know is why temperatures dropped below freezing when it hasn't happened before. I wish I can give you a definitive answer, but I'll tell you, a lot of people are blaming a lot of different things.

I have heard a lot of citing of global waming (which despite its name, ironically makes for colder winters for some parts of the world) that generally mess up global weather patterns.

As suggested by the last answerer - El Niño could be blamed. However, is unlikely because El Niño is a warm current that appears annually around Christmas time along the coast of Ecuador and Peru and lasting only a few weeks. Every three to seven years, the current would lasts for many months, 'causing lasting weather effects.

A more plausable answer might be La Niña, which refers to an anomaly of unusually cold sea surface temperatures found in the eastern tropical Pacific. Because the way the currents work around the world, the westward movement of this cold sea surface temp would dampen the normally warm temperatures of the US western Pacific coast, which is probably why the entire western seaboard saw abnormally cold temperatures. Although I am not certain whether La Niña has been observed this year.

Answer 2

Because Old Man Winter decided to take a vacation to someplace warm.