Here’s a formula to remember when crossing a river, particularly during the high season of melting snowpack and glaciers: Flowing water pushes against things in the stream with a force proportional to the cross sectional area times the square of the average water velocity, according to the University of Arizona’s flow chart.
Translation: If you are one of the “things” and the water is moving about walking speed and the water is over your knees, its pushing force is 70 pounds. The farther into the river, the higher the force; the faster the river, the more force; the higher the river on your body, the higher the force.
With that in mind, here are Sharon’s Rules of River Crossing:
• Common sense is better than no sense.
• Overestimating river speed and depth is better than underestimating. Assume it’s colder, deeper and faster than you imagine.
• Choose wisely. Look for shallow, wide and straight crossings rather than those that are deep, narrow and at river bends.
• Look downriver. If you hear a waterfall or rapids, or see strainers (downed trees in the river that can trap you), or the opposite bank is difficult to climb, choose another spot.
• Speed check. Throw a stick into the water. If it moves faster than you can walk, don’t cross there.
• Depth check. Don’t wade through water any deeper than your crotch. These guidelines are for shallower water rather than riskier, deeper and faster water crossings.
• Look for braids. A braided river is a good choice because the sections are generally shallower and slower.
• What goes up, comes down. The river fluctuates higher as snow melts during the day. It’s lower when it’s cooler, thus less melt. If you have a choice, a morning crossing is better than late afternoon.
• Barefoot is bad. People take off their shoes because they don’t want to get them wet, not because they’re convinced that barefoot is better. Most outdoors experts say you’re more likely to slip in bare feet or cut them on sharp rocks or slip down a steeply angled rock in bare feet.
• Forget fashion. Roll up your pant legs as high as possible because bare legs present less water resistance than wet pants, and you can’t be sure of the depth until you’re in it.
• Stay loose. Loosen your pack’s shoulder straps and unbuckle the hip belt. If you fall, ditch the pack.
• Look where you’re going. It’s easy to get mesmerized by staring at the water coming at you rather than looking at your destination.
• Three legs are better than two, and four are even better. Use a walking stick, planting it firmly ahead of you, and keeping two points on the ground at all times. Or cross with a partner, linking arms to increase the stability level.
• Shuffle along. Cross face the current while angling slightly downstream for the least resistance, and sidestep and shuffle a bit in a downstream direction. Never try to walk normally.
• Keep moving. Water coming from snowmelt is exceptionally cold. Crossing with numb feet is not helpful.
• Pride goeth before the fall. When in doubt, don’t.
• Down you go. If you fall in deeper water, shed the pack and aim your feet downstream. Sidestroke to shallow water.
Best choice: A trail with a bridge or one with no river, especially if hiking with children.
Columnist Sharon Wootton can be reached at 360-468-3964 or www.songandword.com.