REGIONAL—With lower-than- normal rainfall and above-average temperatures in the last several weeks, persistent drought and lower lake and stream levels have become common across a large portion of northern Minnesota.
But the shortfall isn’t just the fallout from a month or two of dry conditions. Much of north-central and now parts of northeastern Minnesota are experiencing what is known as a “storage drought,” the term for a deep and long-term deficit in water reserves, typically caused by years of below-average precipitation. Storage droughts typically take many months or years of above-normal precipitation to overcome.
“A few heavy rain events aren’t enough to pull an area out of storage drought,” said Luigi Romolo, a state climatologist with the Minnesota Department of Natural Resources. According to Romolo, north-central Minnesota is down about 12-16 inches of precipitation over the past four years. “So, it would take months of precipitation far above normal amounts to bring lake levels and soil moisture back to typical levels,” he added.
Although it can be frustrating to those who recreate or live on lakes, varying water levels are not only natural and normal, they are also essential to many important plant and animal species. Low water consolidates lake bottom sediment and can stimulate aquatic plant growth, both of which are helpful to the aquatic ecosystem. For example, some aquatic plants that can’t germinate underwater provide habitat for fish and insects and help reduce shoreline erosion.
“Patience is important when these cycles affect human enjoyment of a lake,” DNR Conservation Assistance and Regulation Section Manager Randall Doneen said. “While many are eager to see lakes at levels more conducive to boating and other uses, people should refrain from activities such as manipulating lake level outlets or undertaking enhanced shoreline alterations during temporary low-level conditions.” 
The long-term drought is also causing very low stream levels across much of the region. As of this week, the Little Fork, Big Fork, and Rainy rivers are all in what is known as Q90, which means their flow is now in the bottom 10 percent for this time of year. The Vermilion River was just above Q90 as of Monday and will likely be in Q90, barring significant rain, when the weekly stream flow numbers are released this coming Monday.
The dry conditions are continuing to expand and intensify the drought conditions in northern Minnesota. According to the latest U.S. Drought Monitor, issued July 30, the area of severe drought has now extended to include the entire Arrowhead.
Lake levels and soil moisture are influenced by not only precipitation but also snowpack, groundwater levels, watershed conditions, and evaporation. Storage drought is often compounded by increased water use, including irrigation for crops or lawns.
“Times of drought remind us of the importance of water conservation. Water use increases as conditions become drier, and that can impact water supplies,” Doneen said. “We encourage all water users to be mindful of how much water they’re using, not just during drought but on an ongoing basis.”