Hike Mt. Shasta

The fact that the Lake Siskiyou Trail had been washed out at the lake’s inlet came as a surprise. I planned on taking my kids to the bridges and letting them spend time throwing rocks and sticks in the river and generally enjoying a morning with the river. While they did enjoy the intended activities, we made it no further than the north shore of the Sacramento River. As it reached the lake, the river ran deep and swift and attempting a crossing was not an option with two little kids. However, once I had ascertained what had happened, I was extremely curious to determine the condition of the seasonal bridge that crossed over the river’s main south channel. Upstream from the waters of Lake Siskiyou, the river splits into two primary channels. The seasonal bridges are installed to cross over both of these channels. Not being able to cross the north channel at the time, I knew that investigation would have to wait for a later date.

Today, I had the opportunity to make the shore hike down to the river from the southern approach. What I found completely defied my expectations. Rather than an area similarly washed out like the Sacramento’s north channel, I found the bridge intact. However, the channel through which the river normally flows was completely dry. This was shocking considering that the south channel had always seemed to be the primary course of the river, usually containing more water than the branch to the north (click here to see the channel with water flowing through it, albeit later in the year when volume is low). Not only was the bridge and channel intact, but the Lake Siskiyou Trail was untouched by whatever massive flood had devastated the bridges and section of the trail a few hundred yards to the north.

Click to enlarge all images

The new primary channel flows past the site of the washed out bridge.

I walked across the bridge and followed the trail over to the site of the northern crossing. As it had the day before, the Sacramento was running swift and deep, carving a new channel out of a broad expanse of river rock and sediment. On the first visit, the landscape had changed so much that it was hard to even guess where exactly the bridge had been located. This time it was possible to follow the trail right to the old crossing. Of course, the wire cages full of rock that had anchored the bridge were gone, as was any other trace that the aluminum span had been there. It was now evident that the southern branch of the river had somehow been stopped up and the full volume of the Sacramento was now being funneled through the north channel.

I returned to the dry southern channel, intending to follow it upstream and find the blockage that had caused the river to radically alter its course. Surprisingly, about 70 or 80 yards beyond the seasonal bridge, I found that water still flowed through the rocky channel. The volume was not great and the water disappeared beneath the rocks before reaching the seasonal bridge. I was equally surprised (though by this point I should not have been) to find that the water did not directly connect to the river but instead followed a subterranean course and emerged from the rocky channel a bit downstream from what turned out to be the old, now defunct split in the river.

The former fork in the Sacramento, where the river was divided into northern and southern branches also revealed more surprises. I was expecting to find a large log jam or other obstruction that had forced the water to abandon the southern branch and to overwhelm the northern channel. Instead, any evidence that the river had split at the site was seemingly erased. The water flowed swiftly through a rocky channel, surging into the northern channel with no opportunity to divert into the southern channel. Where I had expected the log obstruction I found only a low, embankment composed of a vast pile of multicolored river rock. This was somewhat anti-climactic given the destruction the plugging of the southern channel had wrought at the inlet. However, what caused it was certainly mysterious.

It may be difficult to visualize what has occurred. I prepared a few more maps to help illustrate what I have discovered. The first two maps show the area in 2012 when the water level was high and in 2014, when the drought had taken its toll on the river’s flow.

The Sacramento River and Lake Siskiyou in 2012:

Note the heavy flow through the southern channel.

The Sacramento River and Lake Siskiyou in 2014.

The southern channel, though reduced, still retains good flow.

The altered landscape after the washout:

Though this is speculation, I think that the initial obstruction of the south channel occurred earlier in the year, during one of the torrential rainstorms that we had. With the seasonal bridges removed, the result of the southern branch’s obstruction would not have been obvious. The drought then took hold and the river’s flow reduced enough for the seasonal bridges to be installed. Then the snow fell and began to melt. This increased the river’s flow and it was all funneled into the northern channel. This then wiped out the bridges across the north branch of the river. Whatever the order of events, seeing the Sacramento River change its course in such a short amount of time is humbling. Even in this drought ravaged season the river is able to summon up enough strength to alter the landscape dramatically. If nothing else, we should take note of the power inherent in earth in upheaval.

The Sacramento River, just upstream from the former split.

A surging Sacramento River flows past the former site of the seasonal bridge.

It was recently reported that the Lake Siskiyou Trail’s seasonal bridges over the Sacramento River at the lake’s inlet had been installed. This was earlier in the year than normal and it appears that the installation may have been premature. At some point in the last couple weeks the water level rose high enough that it dramatically reshaped the landscape at the lake’s inlet and the river’s course has been altered. Channels that once carried overflow water or ran dry are not the main path of the river as it hurtles swiftly toward Lake Siskiyou. Areas that were once covered in trees and brush have been scoured clear, leaving only an expanse of large river rocks. That this happens is not entirely surprising. The evidence that the river has changed its course in the past is visible in the dry, rocky channels and in the layers of rock and sediment visible in places where the river has cut away small slopes.

The affected area. The image was made when Lake Siskiyou was drawn down. Most of the sandy area on the right is inundated.

One of the most dramatic results of this most recent rearrangement of the Lake Siskiyou inlet area is the apparent destruction of the seasonal bridges that complete the loop around the lake. When approaching from the north shore, the first indication of the damage is a large wooden bridge over what is normally a very small stream. The bridge is visible 10 to 15 yards away from where it should be, washed away by what must have been a furious torrent. Beyond the stream is another, wider creek. This would normally be the location of the first of the three seasonal bridges. Not only is the bridge gone but the wire cages filled with river rock, structures that served as foundation piers for the bridges, are completely gone. Crossing this creek without wet feet requires some tricky maneuvering but once across, the fullness of how much has changed is evident. Any trace of the old trail, the second, larger bridge, and most of the vegetation that flanked the lake’s inlet are all gone. All that remains is a large, rocky area and the swift moving Sacramento River.

I had no idea the bridge and the portion of the Lake Siskiyou Trail around inlet had been wiped out when I took my kids there this morning. I had planned on letting them float sticks down the river and throw rocks. It was a surprise to find the wooden bridge dislodged and the metal bridges non-existent. Nonetheless, once I got my son and daughter across the smaller creeks, they had an excellent time along the river, with or without the bridges.

Given the drought conditions, this kind of damage may come as a bit of a surprise. However, there has been more precipitation this winter than it seems. While the damage is unfortunate, it is heartening to know that so much water has been poured out on the Mount Shasta area. Hopefully the spans will be rebuilt soon and the Lake Siskiyou Trail will be enjoyed throughout the coming summer.