According to the International Lake Superior Board of Control, the lake started the month 38 centimeters (15 inches) above its average level and just a few inches below the record for May. Lake Superior rose 13 centimeters (5 inches) in April, a month with an average rise of 8 centimeters (3 inches).

"The Board advises all those that may be affected to prepare for coastal impacts similar to those that have occurred during the last few years, as the high levels coupled with potential strong winds and waves are likely to continue to result in an increased risk of shoreline erosion and coastal damages across the upper Great Lakes system," the board said Friday in its monthly update.