Mainland Sea Caves - Winter Conditions
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Outer Island Light
Standing on a high bluff at the most remote point of the Apostle Islands chain, the Outer Island lighthouse was built in 1874 to guide ships past the archipelago to the rapidly growing ports of Duluth and Superior.
The handsome brick tower stands ninety feet high, with a design that reflects the Italianate architectural style popular in the 1860s and 70s. Inside the tower, a cast iron staircase spirals up to the "watch room," where keepers serviced the lamp and kept vigil over the beacon. The watchroom is encircled by an outside walkway and topped by the lantern room. The hooded, arched windows and the decorated brackets supporting the watchroom walkway show an attention to architectural detail not seen before in the Apostle Islands.
Sited to cast its beam far across the open lake, the Outer Island light had a large, "third-order" Fresnel lens with a central band of six glass prism bull's-eye panels. These bull's-eyes concentrated the light into six brilliant beams. Rotation of the lens on a clockwork mechanism powered by weights caused the beams to sweep the horizon, making the light appear to flash.
The light station on Outer Island is exposed to the full force of Lake Superior. In its first year of operation, the station dock washed away. Waves eroded the clay banks until they collapsed, destroying the fog signal building at their base. Fierce northeast gales caused the tower to sway so dramatically that keeper O.K. Hall feared the clockwork mechanism would break.
The original fog signal building was replaced by a structure at the top of the cliff in 1875. This move caused the keepers many headaches, as the new location made it difficult to ensure an adequate water supply for the steam-powered whistle. In 1878, a third fog signal building, virtually identical to the second, was built at clifftop, adjacent to its twin. These two buildings were renovated and combined into a single structure in 1900, assuming the form that we see today.
Outer Island is remote. Elna Olson, whose father, Otto, was a keeper on Outer from 1905 to 1914, wrote,
The station changed with improvements in technology. In 1925, the steam fog whistle was converted to an air diaphone run by air compressors and diesel engines. The light was electrified in the late 1930s, allowing it to operate automatically through the winter. The Fresnel lens was removed when the station was fully automated in 1961. Today, solar panels attached to the walkway supply the energy to keep the light burning.
Visiting the Lighthouse
Did You Know?
Lake Superior showed a 79% decrease in ice cover from 1973 to 2010 based on analysis of historical satellite images from that period. - (Wang et. al., 15 Feb., 2012, Journal of Climate)