River crossings are dangerous. Given that it is possible to drown in still water a finger length deep, attempting to cross a deep fast flowing river is very dangerous. One of the most common causes of death in US national parks is drowning. Far more than what most people fear the most.

Any river crossing which is moving faster than walking speed or deeper than knee depth is extremely dangerous.

The first consideration should be: Is there a better/easier place to cross? Could there be a fallen tree over the river further up? Am I willing to risk everything to cross here, or should I hike ‘x’ amount more and stay alive?

If this is the best spot:

River crossing tips

• Use hiking poles. With two poles and two feet, the additional two points from the poles provide more balance. Lift and move these four points one at a time making sure the other three are secure before moving the other. Keep three points of contact to a secure anchor. Place the pole tips down stream and use them to push back against it.
• If it gets deeper or you feel it is getting more dangerous, consider turning back.
• Depending on the situation, consider disconnecting all/some of the pack clasps. With the clasps disconnected, it can be removed more quickly and easily. Consider whether it would be better to potentially lose the pack and all the equipment in it or increase the risk of drowning? 
• Assuming you have a long cord, loop it around a convenient secure point, when crossed, pull it over. If your cord is not twice as long as the crossing, consider using and loosing it.
• Aim to cross diagonally against the direction of flow. The flow will naturally straighten out your path, the flow of water will make your feet land in the direction of the flow.

Group Crossing

• When traveling together in a group, cross together facing each other and hold on to each other’s backpack shoulder straps. Alternatively, use one hand to grip shoulder straps and the other with a single pole. Use your combined mass to make you more secure and provide you with more contact points with the riverbed. Communicate as you move, so only one contact point is off the ground at a time.

Talking with the TRT volunteers this year (2017), I was informed that at least 6 hikers had lost their lives crossing fast flowing rivers on the John Muir Trail. I have no idea what precautions they took, clearly not enough. It is never worth risking everything to ‘bag the trail’, please don’t hike for the sake of your ego and lose your life.