This Spring will go down as the third driest on record for the Tri-Cities as dry conditions continue to plague much of the American West. A total of 0.31 inches of rain was observed during the months of March, April, and May (meteorological spring).
Tri-Cities Driest Springs
| Rank | Year | Precipitation |
| 1 | 1964 | 0.06″ |
| 2 | 1900 | 0.30″ |
| 3 | 2021 | 0.31″ |
| 4 | 1968 | 0.34″ |
| 5 | 1909 | 0.42″ |
Other locations in and near the Columbia Basin experienced similarly dry conditions, with Walla Walla shattering their record. Likewise, Pendleton experienced its driest Spring. Data for Walla Walla Regional Airport only goes back to 1949, however, while data for Pendleton extends clear back to 1894.
Walla Walla Driest Springs
| Rank | Year | Precipitation |
| 1 | 2021 | 1.09″ |
| 2 | 1964 | 2.73″ |
| 3 | 1968 | 2.75″ |
| 4 | 1992 | 2.78″ |
| 5 | 1966 | 2.88″ |
In the Tri-Cities, it might actually be that this was the second driest on record. The year 1900 only recorded 0.30 inches of rain during the Spring months, but two months of data are missing. This is not uncommon for records from over a century ago, but is unfortunate nonetheless. Either way, 2021 was definitely the driest year so far in the 21st Century.
Part of this story can be told by wind patterns. On average, April is the windiest month in the Tri-Cities with an average speed of 8.4 mph. While the Columbia Basin certainly saw its fair share of wind this Spring, the April average only comes out at 7.2 mph.
Perhaps more interesting is the direction the wind was sourced from. The majority of wind observed at the airport is out of the west-southwest – typically the result of wind passing through the Cascades from the west. This April, and indeed the other Spring months as well, several days of northeasterly winds were dominant in the region. Rather than being sourced from the Pacific Ocean, many of the regional weather disturbances this spring came from the Canadian interior. These systems, similar to the storm that came through Labor Day 2020, are often drier than disturbances coming in from the west.
Spring 2021 Driest Precipitation Rankings
| City | Spring 2021 Rank | Precipitation | Year Records Begin |
| Ephrata | 2nd | 0.32″ | 1949 |
| Pendleton | 1st | 1.01″ | 1894 |
| Tri-Cities | 3rd | 0.31″ | 1894 |
| Walla Walla | 1st | 1.09″ | 1949 |
| Yakima | 2nd | 0.17″ | 1947 |
The drought gripping the Western United States continues to worsen. In the May 27 update of the US Drought Monitor, extreme drought (D3/4) is slowly working its way into the region. Current indications are that there won’t be much relief during the summer. Luckily the drought does yet not extend to the Washington Cascades. Hopefully this will help to mitigate some of the impacts to parts of the Columbia Basin that benefit from irrigation.
Meteorological spring ended on May 31, with the beginning of June marking the start of meteorological summer. For record keeping, meteorologists use months rather than the solstices and equinoxes because the latter vary each year while using the months allows for more standardization.
Data in this post were sourced from NOAA and Iowa Environmental Mesonet.
