2019 was another banner year for precipitation in Minnesota, with over 20 individual annual precipitation records set, and the state turning in its wettest year on record.

Precipitation totals for the year exceeded 30 inches over all but about 5-10% of the state, mainly in far northern Minnesota, with totals exceeding 50 inches in parts of southern and southeastern Minnesota. Well over half of the state was 12-20 inches (or 50-70%) wetter than normal. Annual surpluses of that magnitude over such a large area contributed to 2019 being Minnesota's wettest year on record, on a statewide-average basis, with an average of 35.51 inches. This eclipsed the old record of 33.93 inches, set in 1977.

Although no climate observing station was able to break the statewide individual annual precipitation record of 60.21 inches set by Harmony in 2018, many stations with over 50 years of observations did break their own annual precipitation records. Rochester International Airport led the pack with 55.16 inches, breaking its old record by more than 11 inches.

The Twin Cities International airport, part of the longest station history in the state, had just broken its record in 2016, but broke it again in 2019, with 44.17 inches. Other records fell throughout the state. The majority of these stations broke records that had been set this decade.

Even closer to home, the ACD has utilized the precipitation data collected by our volunteer observers to assist with putting our monitoring well data in context. We have observed sustained wetland hydrology because of the abundance of precipitation. How this will affect how wetlands are managed in the present and future will need to be addressed by the current wetland regulatory rules and by utilizing the data we collect when reviewing wetland delineations.

This information is provided at the DNR Climate website:https://www.dnr.state.mn.us/climate/journal/top-weather-and-climate-stories-2010s.html

Here is a partial list of the records set this year.

by Fred Baker, Emeritus Professor and Forest Pathologist, Utah State University

Eastern spruce dwarf mistletoe is a disease that kills trees quickly, with most trees dying within 20 years. In Minnesota, this mistletoe typically affects black spruce, an important species to the state's forest products industry and landscape.

The dwarf mistletoe disrupts a tree's physiology in incredible ways. The most common sign is the formation of a witches' broom. In this process, the disease diverts the tree's nutrients to the broom and "starves" the rest of the tree. Ultimately, the tree will die because it's unable to process the lipids it needs to survive.

Witches brooms in a dwarf mistletoe-infested black spruce stand. Photo: Brian Anderson.

Dwarf mistletoe is a parasite. It flowers in March and is a safe bet to be the first "plant" to flower in the spring. Seed dispersal happens in late August and early September. When seeds disperse, dwarf mistletoes are unique because they can shoot their seeds up to 55 feet from a diseased tree! These seeds are covered with a sticky substance that attaches to a nearby spruce needle. During summer rainfall, this sticky substance rehydrates, and the seeds slide closer to the twig, where it germinates the following spring.

Although dwarf mistletoe can shoot seeds up to 55 feet, most only go a few feet. This results in a spread rate of about 2.4 feet per year through a forest stand. Research indicates that spread from large trees and small trees is about the same. Slightly more than half the spruce stands in Minnesota are thought to be infected with dwarf mistletoe.

Mistletoes are obligate parasites. This means that if you kill the tree, the parasite dies too. If timber harvesting is done in black spruce, removing all spruce trees during a harvest could minimize the risk of mistletoe infecting a future stand.