MONTHLY REVIEW

The big story for February 2021 was the historic snow and ice storm that wreaked havoc on the area. With the Portland Metro being right on the snow/ice boundary, the area was subjected to several types of frozen precipitation depending on the geographic location and day. A very strong High Pressure system centered north of the area and Low Pressure to the south caused very strong east winds to blow through the Columbia River Gorge, resulting in much of the Portland Metro’s rainfall, which began in the early morning hours on the 11th, changing to a period of freezing rain and sleet then eventually to all snow, especially in the northern and eastern parts of the area. Here in Happy Valley at an elevation of 600 feet, the changeover to snow occurred in the late afternoon of the 11th and continued into the overnight hours before changing to a period of freezing rain prior to sunrise on the 12th, the snow and some sleet totaling 2.6″ at 0700 Hrs and the freezing rain accreting to 0.1″ at that time. The mixed precipitation quickly changed back to all snow and another 2.0″ was measured by 1300 hours on the 12th. This continual back-and-forth changeover from snow, sleet, and freezing rain continued for two more days, with the snow/sleet final total reaching 5.8″. However, the larger issue was the subsequent extensive period of freezing rain that continued into midday on the 14th, accreting to a maximum of 1.0″, covering everything under a very heavy weight of ice. Everywhere one looked vegetation damage was evident and extensive – the resultant weight of the ice itself bringing down many power lines, with falling trees and branches causing even greater damage to the lines (and even to buildings), resulting in extended power outages throughout the Willamette Valley, especially the farther south and west. It was also reported that more than 4,000 power lines were affected, not to mention the many damaged transformers. Due to the ongoing freezing rain and associated wind in various areas, power would be restored only to be taken offline again. More freezing rain was predicted for the night of Feb. 14th (an Ice-Storm Warning was in effect from the National Weather Service) but temperatures, at least here in Happy Valley at higher elevations, rose above freezing and it stayed as plain rain, otherwise damage would have been even more severe. Areas that received more snow were fortunate as less freezing rain caused fewer major issues. At one point it was reported that around 300,000 electric customers were without power, with some locations going as many as two weeks before power was finally restored. Many area roads had to be closed due to the sheer number of fallen trees and power lines. The sound of chain saws and the smell of smoke from subsequent burning of tree debris continued for weeks afterward. 

 

TEMPERATURES

February 2021 averaged below Normal for both Maximum and Minimum Temperatures, with official area locations having Mean departures from -2° to nearly -4°, with Maxima contributing more to the departures, ranging from -4° to -5°. The month began on a relatively mild note, with Maximum Temperatures here in Happy Valley remaining in the 40s to near 50° through the first 10 days. By the 11th of the month, strong east winds coming through the Columbia River Gorge brought very cold air in from the central U.S.  Temperatures remained in the 30s or colder from the 11th-14th, with the Maximum of just 27.2° on the 12th being the Coldest Maximum Temperature not only for the month of February but also for any month since this station was established in May 2014 (it was also the first February Max. Temp. ≤32°). The remainder of the month stayed in the 40s, not rising above 50° until the very end of the month, reaching 50.6° on the 27th and 56.4° for the month’s highest on the 28th.

Minimum Temperatures followed a similar path, with 30s and 40s over the first 8 days of the month, then chilly air settling in with sub-freezing readings from the 9th-14th, the only such temperatures of the month (the coldest falling to 23.9° on the lucky 13th. The greatest daily range was 23.6° on the 7th (60.1°/36.5°), the least 3.8° on the 15th (45.0°/41.2°).

The greatest diurnal range was 13.9° (56.4°/42.5°) on the 28th, the least just 2.7° (27.2°/24.5°) on the snowy/sleety/icy 12th.

 

 

 

MONTHLY WEATHER FORM: FEBRUARY 2021

 

Cover Photo: Freezing Rain Street-Tree Damage – 2/15/2021.