As Great American Eclipse chasers head home from communities on the path of totality, southbound traffic on Interstate 15 in Idaho is heavy.  

Vehicles were bumper-to-bumper on I-15 Monday afternoon, moving 5 to 15 mph at times as drivers headed south from Idaho Falls toward Pocatello. Some drivers on that stretch moved 35 to 40 miles in more than two hours. Typically, it takes about 45 minutes to travel between the two towns.  

Traffic on U.S. 95, with vehicles headed south out of Weiser, also was moving slowly Monday afternoon.  

Utah Department of Transportation spokesman John Gleason said the heaviest delays on I-15 and other interstates in Utah were expected Monday evening. He advised resident drivers rethink their travel plans to avoid southbound lanes in particular, which were expected to be clogged with sun-watchers heading home.

Travelers can stay up-to-date on traffic conditions by visiting UDOT’s website at udottraffic.utah.gov.

To accommodate the congestion, UDOT suspended work on numerous construction projects on I-15, reopening all lanes Monday, or shifting traffic temporarily to increase capacity.

The best view in the region was some 220 miles north of Salt Lake City where the rare, cosmic event’s path of totality tracked through southeastern Idaho in the Twin Falls to Idaho Falls areas. There, for 2 minutes 40 seconds, the moon obscured the sun before continuing on to points east.

In Monday’s predawn hours, traffic on I-15 had approached levels usually not seen until the height of the morning commute as drivers headed north for a prime view of the solar eclipse.

As expected, traffic slowed to a crawl — 10 to 15 mph in places — as of 7:15 a.m. on I-15 in Box Elder County, approaching the Interstate 84 exit toward Twin Falls to the northwest, as well as the congested stretch straight north toward Idaho Falls.

Utah Highway Patrol Sgt. Jacob Cox noted that while the morning commute was heavy, there had not been an corresponding increase in crashes reported. By late morning, the flow had eased to more normal levels. Still, troopers were on alert for congestion expected in the afternoon and evening hours as eclipse viewers head south on their way home.

The U.S. landfall for eclipse’s totality path was 11:16 a.m. MDT in Newport, Ore., and from there the shadow headed through central and southeastern Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee and Georgia before exiting the continent at Charleston, S.C., at 12:48 p.m. MDT.

The Utah Department of Transportation braced for an estimated 50,000 additional vehicles on the interstate freeways over the weekend leading into Eclipse Day. That traffic flow increase, above the usual 200,000 vehicles that traverse I-15 on a normal weekend, was expected to continue through much of Monday as eclipseophiles first head north to see the event, and then drive back afterward.

Gleason had several suggestions for those chasing and returning from the eclipse:

• Don’t leave without a full tank of gas. Trying to get off freeways to fill up at rural gas stations, likely already inundated due to heavy demand, will be a challenge.

 • Bring along extra food, water and snacks.

• Expect spotty cellular phone coverage.

• Plan on your post-eclipse trip home taking extra time. Indeed, you might just wait a few hours or long before heading back.