IMCDA weather/water temp info
There have already been a few posts about this. But here is a quick summary and some hard and stylized data for those interested. Summary: historical weather and water temps have been highly variable. As others have mentioned, bring everything and figure it out day before race day. Things can and usually do change, making long range weather forecasts and even 1-week-before water temp unreliable guides. In one man's opinion, not something to obsess over. Having said that, here are some facts and SWAG projections:
The following table was built from daily water temp data for Lake CDA from the USGS which can be found here:
http://waterdata.usgs.gov/nwis/dv?c..._module=sw
The table:
| 2007 | 2008 | 2009 | 2010 | 2011 | |
| June 1st | 61.3 | 53.9 | 60.1 | 53.6 | 50.2 |
| 1 week before | 59.4 | 59.2 | 65 | 58.1 | |
| Race Day | 63.5 | 65.5 | 65.5 | 61 | |
| Increase from June 1 | 2.2 | 11.6 | 5.4 | 7.4 | |
| Average in from June 1 | 6.65 |
It is also worth noting that the data shows a fair number of days in June where the water temp changes by ~2 degrees from beginning of day to end of day.
Current 10 day forecast (which gets us within 6 days of race day) shows high temps in the high 60s with roughly half the days containing material sunshine. This compares to an average historical temp of mid 70s (at least 11 days through 17 days from now). Ignoring snow melt run-off and rain, and assuming days 11 through 16 maintain the same basic trend (and that the 10 day forecast is accurate, see disclaimer above), one could speculate that the lake won't warm-up as much as in 2008 & 2010. Still reasonable to assume something in the high 50s though with a chance of hitting 60. Brisk, but eminently swimable and will LIKELY mean that most of us won't use a neoprene cap.
Comments
The piece of the analysis that is missing is the comparison of snow packs. This year we have had record amounts of snow in the mountains and each time the air temps rise, snow melts and runs into the lake, which temporarily decreases lake temps. Once the snow packs are gone, if the temps stay in the 60s/70s the lake will warm fairly rapidly.
With that in mind, the warming trend of Lake CDA is much less than linear - I'd give it a VI of 1.2+.
In the meantime, as was said before, worrying about Lake CDA temps is a lot like worrying about my hair falling out - I don't have much control over either event so I might as well concern myself with other stuff.
P.S. I just finished one loop of the IM CDA bike course this morning and it was magnificant. Like the past three Saturdays where we did a loop temps were in the 70s by the time we finished right around noon.
In '08 the water temp was about 54 when I swam on Wednesday. Felt like someone had punched me in the face. Race day was about 58. But, like Al said, ain't nuthin' you can do about it other than show up prepared for a (potentially) cold swim.
@ Rich, do ear plugs somehow help keep you warm or is there another reason for them?
Comments on what to wear in cold water. The year it was 58 (I'll take Rich's word it was 08), athletes were allowed to wear booties without penalty (meaning they would still be able to qualify for AG awards and/or Kona). Other years, above 59.9, booties mean you are out of the awards no matter your time.
I wore booties and a neoprene cap that year. My time was slower by 3 minutes than almost every other IM swim I've done. Even with the wet suit leg pulled OVER the bootie top, water still crept into the boot, making it heavy and thus a drag off of horizontal. If it's that cold this year, I won't wear them.
I do wear a neoprene hat below about 62F. I also consider wearing arm "warmers" beneath my wet suit. I always wear ear plugs in an IM swim, 'cause my ears plug up otherwise - uncomfortable on the bike if you can't hear. I did learn in medical school that cold water in the ear canal can induce vertigo - that might be what Rich is counteracting. I don't think it will make you any warmer.
If you're going to obsess about environmental conditions, wind on the bike and temp on the run are much more important, considering the effet on your final outcome and how long yo have to be out on the bike or run course. Also, the harder you swim, the warmer you'll feel. Just sayin'.
Also, the harder you swim, the warmer you'll feel.
I am one who is bothered when my ears are plugged. That same year I wore a neoprene hat which covered my ears and it bugged me the entire way. Again, for me at least, lesson learned about keeping my ears uncovered. I have swam, ears uncovered, in significantly colder water with no ill effects - at least as far as my ears are concerned.
As always, before attempting this stuff in a race, try it out during practice.
As AL said, figure out if you have ear sensitivies (one way or the other) in practice first!
yes, referred to as cold caloric response. it's actually a normal response and used to test proper functioning of brain stem. some people are more sensitive than others. a friend of mine got it during a race. he flipped on his back until it went away and then it never came back and he finished the swim fine.
if this happens to you in the swim, stay calm, flip on your back or start side stroke and wait for it to pass....or wear ear plugs. it should not return once the external ear canal adjusts to the cold: a few minutes.
gh
I swam it in 2008. Cold shot to the face but nothing that can't be overcome by jumping in a few mins before the gun and splashing around. I wore a neoprene cap and liked it. Yeah, feet were cold but that went away in the first half hour of the bike.
I still think we are going to settle around 60-62 on the day. I don't have a ton of faith in Accuweather but it shows on the long range that there will be a big high pressure and higher 70's low 80's at the beginning of next week.
the only water temp i am worried about is the one where they don't allow wetsuits!!! that would SUCK, but i think we are safe there. as for 80 on race day outside the water, that's what we did had at RR1 AND wind....hehehehe.
80 degrees today and tomorrow in Pasadena, california. nice preview in case it gets that warm at CdA.
gh
@Gil, I think we're safe with the water temp for wetsuits. Given the temperature forecast I would almost say its almost impossible.
The water will be 61.7 F on race morning. You can bank on it,
As long as I'm predicting, it will rain on Friday (maybe the morning?) before the race, then be breezy and cooler on Saturday, "warming" up to 71 F on Race Day. Wind won't be a factor. Or anything else between 48F and 88F.
If it DOES rain soon before the rave, we'll need to be very cautious running to our bikes in T1 - it's grassy and in the shade, and could easily be a soggy mess. Consider carrying shoes to the bike, and not putting them on untill hitting the blacktop leading to the exit chute.
art: i think al's forecast is a good compromise between our desires for the weather, right?
thanks very much for those suggestions, AL!!!!!!!!
gh
While I do stand by my water temp prediction, rest assured that my weather prediction was a total fabrication, based on my fantasy of the ideal day!
oh no! then that means the weather truce between Art and myself is off!!!
i wish for 80
. (superstitious folks who might get freaked out by my wish, do not worry. my prayers have never been answered!).
as long as greg doesn't say anything, we are safe.
gh