On February 20, 2013, a chunk of the Echo Cliffs gave way and slid downhill. It took about 150 feet of US Route 89 with it. A twenty-three mile section of the road is now closed in Arizona between the US 89A junction near Bitter Springs and the State Route 98 junction near Page.

The location of the damaged highway is particularly unfortunate because it closes the most direct connection between Flagstaff and Page. For now, the shortest way around the closure when traveling north is to take US Route 160 east through Tuba City for fifty miles to Arizona Route 98. Go northwest on 98 through Kaibito for sity-seven miles to Page. Reverse those directions if you are traveling south from Page. The detour adds about forty-nine miles to the trip.

There will soon be a shorter detour. The Navajo Nation and the Arizona Department of Transportation have reached an agreement to pave an existing dirt road that parallels US Route 89 from The Gap to Page. Completion of US 89T is schedule for this summer and will make the trip between Flagstaff and Page about the same distance and time as US 89.

If you are heading north into Utah, US Route 89A from Bitter Springs is your best bet. This route crosses the Colorado River, passes through House Rock Valley, climbs over the Kaibab Plateau to Freedonia, Arizona, and rejoins US 89 in Kanab, Utah. This alternative route is the original US 89. The road that is the subject of the closure was built in the 1950’s for trucks carrying materials for the construction of Glen Canyon Dam near Page.

Vermilion Cliffs sunset from Echo Cliffs overlook on US Route 89

Another unfortunate consequence of the closure is that travelers will not be able to experience the beautiful view across Marble Canyon to the Vermilion Cliffs. I have enjoyed this view many times and will miss it until the road is reconstructed. I will also miss stopping at the pull-out near the top of the cliff to shop for hand-crafted Native American jewelry.

Geology of the Slump

Thanks to geologist Wayne Ranney from Flagstaff, I have a better understanding of what happened to cause the collapse of the roadway. He has written several articles on his blog, Earthly Musings.

To put it in layman’s terms, there is a soft layer of rock at the bottom of the Echo Cliffs called the Chinle Formation. This is the formation that makes up the Painted Desert and is composed of colorful mudstone and shale which expands when it is wet and contracts as it dries. At the top of the cliffs is the Navajo Sandstone, a much harder rock layer that forms vertical cliffs as it erodes.

In the photo below from Google Earth, an ancient slump is clearly visible in the highlighted area. A section of the Navajo Sandstone has slid down the slope as the softer rocks below gave way. The highway was built over this slump area and when it moved downhill on February 20th, it displaced the pavement by about six feet.

Geotechnical engineers from ADOT have been on the job trying to determine if the slump is still moving. There next task will be to determing how to rebuild the highway across this section so that it doesn’t keep going downhill. There is no announced time frame for the repairs but I have heard two years bandied about.

To keep the public informed on the progress of reconstruction the Arizona Department of Transportation has added a special page to its website. There is a very dramatic slide show of photos of the damage to the roadway on this page. ADOT also has a blog which has occasional articles about Highway 89.

If you want more information about the geology of this region, I recommend subscribing to Wayne Ranney’s blog, Earthly Musings.Another good source is the blog of the State Geologist of Arizona, Lee Allison.

An event like The Big Slump reminds us just how fragile our highway system can be and how powerful the geological forces are. If there is a silver lining is this event, it is that travelers will get to see a landscape on the Colorado Plateau they might not have otherwise. Allow a little extra time and enjoy the scenery.