a look up at science


February issue curated by Alex Martin

February Highlight

Lakes, Oceans, and Winter Weather

Why does snowy weather seem to hit heavier near lakes than the ocean?

When’s the last time you saw snow on an ocean-side beach? Chances are, you can’t picture the scene in your head. Wouldn’t the waves wash the snow away? Isn’t the air too salty to form snow on the coast?

It turns out, snow on a beach isn’t uncommon, we just rarely associate beaches with snow. But it happens, and one impressive example occurred in early February, when Oregon’s Cannon Beach and its famous Haystack Rock were covered in a blanket of snow.

Let’s think about this: when you visit a beach, it’s usually much windier than further inland. Coastal regions also tend to be cooler in the summer months, and warmer in the winter months, as compared to those more inland regions, and there’s a reason: the Maritime Effect.

The Maritime Effect is a unique property of ocean coastlines: the thermodynamics of large bodies of water, that is, how heat is transferred and stored in the oceans, show us that oceans cause a regions climate to remain more stable throughout the year, as compared to areas farther inland.

Sunlight is constantly hitting the ocean, and so the heat from all that light is stored within the ocean water and humid air. Water is able to store a lot of heat, and the ocean is constantly moving, so heat is distributed and recycled evenly, and doesn’t fluctuate heavily through each season. This provides a stable range of temperatures that leads to a reliable spectrum of weather patterns.

Farther inland, the opposite phenomenon occurs: the Continental Effect. Dry surface lands absorb a lot of heat during the day, but aren’t able to evenly distribute it like in the ocean. This leads to “hotspots,” areas of uneven heating. At night, without substances to retain it, much of the heat is lost. These drastic day-to-day changes are what allow for wide changes in day-to-day weather patterns. It’s also the reason deserts can be so hot in the day—the dry ground collects and immediately releases a lot of heat; but be near-freezing at night—very little heat remains stored in the ground to be released into the air.

The last effect may be the most popular, brought up nearly every winter: the Lake Effect. In the United States, the Lake Effect is most common in the Great Lakes region, and is accountable for why cities such as Buffalo and Chicago can see several feet of snow pile up very quickly in the winter months.

Large lakes collect and store a lot of heat. But lakes are land-locked, and aren’t able to transfer that heat all around the world, so it builds up through the summer months. Heated water evaporates easier, so by the time winter settles in, the atmosphere around the lakes remains humid. Finally, when a cold front sweeps across the lake, the humidity condensates and is quickly precipitated as snow just off the coast.

Lots, and lots of snow.