The Keystone pipeline will benefit Canada by allowing them to get their crude more easily to international markets where they can get a better price for it.
It will also keep 1 million barrels per day in a tanker floating on the seas where "winter hurricanes" are common!
Unimak Pass is about 800 miles southwest of Anchorage.
David Mosley, public affairs specialist for the U.S. Coast Guard in Alaska, says that the thousands of ships that already navigate its waters each year
face "winter hurricanes" with 40-foot seas and 100-knot winds that appear with little advanced notice.
Large ships must ride out the storms in sheltered coves in the Aleutians.
In a typical year, at least one ship gets into trouble. "A vessel will have some sort of mechanical or physical issue that then puts them at the mercy of the weather and the waves."
The Environmental Dangers of em Not em Building Keystone XL - Popular Mechanics