How Reliable are Ratings?
By Otterboy
One of the first things newbie
paddlers learn is the
International Scale of River Difficulty.
When I was first learning to kayak, I checked out all the local
Class II runs and worked hard to move up to Class III, and then
IV. The ratings scale provided a great tool that allowed me to
decide which rivers I was capable of running.
However, our standard rating scale has some significant flaws.
The biggest issue is that no single system of categorization can
adequately describe the dynamic, chaotic environment that is a
flowing river. By pigeonholing a specific rapid into a I-V
rating (ok, technically it's I-VI, but if you run Class VI drops
you certainly don't need my advice), the ratings scale gives the
appearance of certainty in a fundamentally uncertain
environment. By relying too much on a ratings system, paddlers
can lose sight of what really keeps you safe - your own skill,
judgment and the support of your buddies.
This was brought home to me in a very
real way during the spring of 2007 on the
Tilton River. I was getting ready to put
on with a strong group of paddlers when a guy drove up and asked
to join our group. We asked him the usual questions, can you run
Class IV, can you roll, etc. Satisfied that he was a solid
boater, we invited him along. I knew we were in for a long day
when he portaged the first Class III drop. He ended up swimming
just about every rapid. I took a lot of lessons away from the
experience. Bottom line, as a group we made the assumption that
just because this guy had run Class IV in the past he'd be fine
this particular day. If we'd asked a few more questions we would
have found out that he didn't boat a lot, was having trouble
with his roll, and was testing out a new playboat. He was a good
guy, just in over his head (and deep in the Tilton River
canyon). The most important lesson was that there are so many
more factors than simply the nominal rating of the river.
This last May I organized a drip down
the
Foss River. There were 4 of us, two Class IV paddlers
and two up-and-coming Class III paddlers. The flow was 12,000 cfs on the Skykomish at Goldbar gauge. The
Class III guys joined
us midway through the run for the lower section, which is rated
III+ by both Jeff Bennett and American Whitewater. It was a bad
day, to say the least.
Click here for a full trip report. Our
fundamental error was to rely too much on the III+ rating rather
than question whether a high water run on the Lower Foss was a
good place to introduce Class III paddlers to creeking.
Another flaw in the international system is that it does not
give you much detail about the actual type of rapids involved.
For example, Class IV creeking is very different from Class IV
big water. Compare the
Upper Lochsa with a pool/drop creek like
Silver Creek (tributary of the
North Fork Skykomish River). Both are Class IV, but the
character of each river is totally different and calls for
different skills. Personally I prefer creeking over, well, just
about anything else. When you're creeking, it's all about hitting
your line. You may miss a frothing portal to hell by 6 inches,
but those 6 inches are as good as missing it by a mile. On the
occasions when I jump on a high volume river, it always takes me
a couple of rapids to get into the zen of big water. Last time I
ran the
Crooked River I was discombobulated for a while simply
because the giant waves threw my little creek boat all over the
place. I'd get surfed 10 feet to the right and freak out because
I thought I was off my line. Eventually my nervous system
figured out that the line down a Class IV wave train was larger
than boofing off a ledge and I relaxed.
There are several others limitations in the international rating
system. When does high water turn a Class III run into a Class IV maelstrom? When does a dangerous feature like an
undercut increase a rapid’s rating? What about a wilderness trip
vs. a roadside run? There have been attempts to modify the
International River Scale to account for these factors. The most
ambition is the
Addison Scale, developed by South African
paddler Corin Addison. Rather than a single number on a 6 point
scale,
Some examples are:
I’m usually biased towards having more information rather than less. Still, I’m not convinced that adoption of this scale would be a net gain for the paddling community. First, there’s the issue of agreeing on whether a specific river feature is a “4”or “5” (or whatever) for danger. We would have a replay of our current arguments about whether a rapid is Class III+ or IV-, only with three times the factors to bicker about. But most of all, this would move us further toward reliance on an external categorization system rather than our own eyes and paddles.
I’m certainly not suggesting that we should abandon ratings entirely. Used properly, any rating system will give you a good idea of what to expect and inform your decision on whether to paddle a given river in the first place. When I’m running a difficult river, especially for the first time, I go with a strong group that I trust. The next step is to scout it. Actually looking at the rapid gives me more information than any ratings system ever could and allows me to use the nominal rating properly – as a rough guide to what I should expect. Ultimately, no number can substitute for your own experience and judgment.
Good judgment comes from experience.
Experience comes from bad judgment. -
Jim Horning