Yesterday, a friend and I repeated our Towpath hike from Brunswick out to the site of the culvert washout. As the pictures below show, it is still closed. They seem to have started building the temporary "low bridge" - it is hard to see in the picture, but past that large pile of gravel in the water are several pieces of drainage pipe that were to span the creek and be covered with gravel to let hikers/bikers cross. However, the Potomac River is so high (normally that pile of gravel is on the dry bank) they are probably waiting for the creek to get back to normal levels. There are two backhoes sitting nearby.
At the level the creek is now, the only real way to cross is on the railroad tracks.
The outage - those cyclists are on the downstream side.
Normally that pile of gravel is on the dry bank, just past it to the left you might be able to see the drainage pipe in the creek that shows they have at least started on the temporary low bridge.