On August 21, 2017 a total eclipse of the sun will be visible from within a narrow corridor that traverses the United States.
The total solar eclipse of August 21 is the first total eclipse visible from America’s lower 48 states in over 38 years. The last one happened in 1979 and passed through the Pacific Northwest and central Canada in late winter.
The total eclipse is visible from within a narrow corridor that traverses the United States from the Pacific Northwest to the Southeast crossing a dozen states: Oregon, Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and South Carolina (a tiny corner of Montana and Iowa are also inside the path). A partial eclipse is seen within the much broader path of the Moon’s penumbral shadow, which includes all of North America, the northern third of South America, and westernmost Europe and Africa.
The central path begins in the North Pacific about 2400 kilometres west of North America at 16:49 UT1. The Moon’s umbral shadow travels 28 minutes before making first landfall along the Pacific coastline of Oregon at 17:16 UT1 (10:16 am PDT). The Sun’s altitude is 39° during a totality lasting 1 minute 59 seconds. Unfortunately the Oregon coast is often subject to heavy morning fog, making it a concern to eclipse watchers.
Rushing east, the umbra crosses the 3,000-foot-high Coast Range and into the Willamette Valley. The cities of Corvallis, Albany and Salem all lie deep in the path and have durations ranging from 1 minute 40 seconds to 1 minute 55 seconds. Coastal fog rarely comes this far inland and the mean cloud amount from ground records is ~50%.
The 10,000-foot-high Cascade Range tends to have a drying effect on the air as the shadow descends into the Columbia Basin. This region is notable for having the statistically lowest cloud amount (25%) along the entire eclipse track. Madras residents get just over 2 minutes of totality. The area will be a major draw for the eclipse and most hotels are already booked.
The elevation through eastern Oregon gradually climbs as the path reaches the Idaho border and the Snake River Plain. While Boise, Idaho’s capital, lies just outside the eclipse track, it’s only a short drive to get into the path of totality early on eclipse day. To the east, Idaho Falls is deep in the path where totality lasts 1 minute 49 seconds. The duration is 2 minutes 18 seconds from the central line 34 kilometres further north. The weather prospects here are nearly as good as central Oregon.