 The West Wind Drift splits into the northward flowing branch which meets the Humboldt Current and the southward flowing Cape Horn Current, providing ample heat to drive vaporization of the sea water, which results in onshore precipitation of 4,000 – 7,000 mm per year in the Chilean Andes.The moisture is driven onshore by prevailing westerly winds, the Roaring Forties.The fjord was explored by Enrique Simpson in 1870 in the "Chacabuco" who discovering its usfullness to access more inland locations.