Snow is undoubtedly one of the highlights of the winter season for many people. From hitting the slopes on Mount Hood to relaxing indoors with cocoa, there’s something for everyone on a snowy day. The chance for snow excites many in the Portland area, as it’s not every winter that the Metro sees it. The weather conditions have to be perfect to get snow, and even then it can be hard to accurately predict snowfall. Many Oregonians doubt whether or not it will snow this winter.

Snow can be a rather picky condition to form, the Atmospheric temperatures must be at or below 32°F to form snow. Meanwhile, surface temperatures can be no higher than 35°F for the snow to fall, and sub-freezing for it to stick to the ground. A common phenomenon to happen during snowfall is albedo. Albedo is the reflection of light. In this scenario, it’s the reflection of sunlight off of snow. Because the sunlight is reflected off the snow, heat can’t penetrate and warm the ground. Temperatures begin to decrease, and snowfall tends to increase, due to the temperature drop. This means that even if the temperature is above freezing, the snowfall itself may actually lower the temperature enough for the snow to stick. Portland often sees situations like this, with mild valley winters, the chance for snow is often wedged between a narrow few degrees. 

Snow lovers across the Metro often worry if no snow has fallen by mid-December. However, the average time frame for snow in Portland doesn’t begin until January 6th. But this still begs the question- can Portland expect snow this winter? Short answer: Yes. Lucky for those who flush ice cubes down the toilet, put spoons under their pillow, and follow all other snow wishing procedures, snow is very probable this winter.

 Many wonder why some years get a lot of snow, others get none, and why all follow a consistent pattern. El Niño versus La Niña, the two weather patterns that create predictable average weather conditions worldwide. El Niño is characterized as having warmer than average sea temperatures, and often drier weather conditions in parts of the United States. Contrary, La Niña is known for having colder Pacific temperatures, and wetter weather. These patterns often affect different regions of the United States in very different ways. For example, a La Niña cycle typically means warmer, drier conditions in the midwest. Meanwhile colder, wetter conditions can be expected in the Pacific and northern parts of the country, and vice versa.

The 2020 – 2021 season was declared to be La Niña, which means Portland can expect above-average snowfall this winter. Last time the area saw a La Niña winter was the 2017-2018 season where 7.5 inches of snow fell, 4 inches above the yearly average of snowfall in Portland. Because of this increased chance for frigid weather, it’s important to prepare in advance. Have snow chains ready to use, purchase rock salt, gravel, or a de-icer if necessary. And make sure to have appropriate attire for sub-freezing weather. 

Of course, there is no guarantee when it comes to weather predictions. 100% certainty is impossible when guessing the future. However using historical weather data, we can compare present times to past times and make an educated guess on a future event. The task of prediction is often thought of as looking into the future, but more often than not predictions are made by looking back in time. Because when looking into the future, look no further than the past.

Sources & Citations:

Albedo. (n.d.). Retrieved December 18, 2020, from https://www.britannica.com/science/albedo

Strong La Niña Is Possible This Winter. Here’s What That May Mean for the United States: The Weather Channel – Articles from The Weather Channel. (n.d.). Retrieved December 18, 2020, from https://weather.com/news/weather/news/2020-11-12-strong-la-nina-possible-what-means-us-winter

Portland, OR Weather Historystar_ratehome. (n.d.). Retrieved December 18, 2020, from https://www.wunderground.com/history/monthly/us/or/portland/KPDX/date/2018-10

Editor. (2018, January 12). How to Prepare for a Snowstorm – A Winter Storm Checklist. Retrieved December 18, 2020, from https://censtarenergy.com/prepare-snowstorm-winter-storm-checklist/