DULUTH, Minn. (AP) -- The breathtaking ice caves along the Apostle Islands National Lakeshore will likely be inaccessible this year, due to low ice coverage on Lake Superior.

As of Friday, less than 5% of Lake Superior was covered by ice, much lower than the typical 25% of coverage at the end of January.

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While ice coverage on Superior typically peaks in February or March, data shows most winters with this level of ice on Jan. 31 don't accumulate much more.

Reports say the last time the ice caves were accessible by foot was in 2015.