When does the season start?

A few people have been asking when the river surfing season starts. I’ll focus on River Run Park, since that’s the wave people are frothing over, at least in Denver.

USGS gauges are a great resource to answer this question, since their data goes back years, and you can extract data for whatever time period you’re interested in. Here is a graph of RRP’s flows from April to the end of July last year:

2017 River Run Park Flows

Snow pack as of April 1, 2017:

April 1, 2017 Chatfield Storage: 24,827 Acre Feet

April 1, 2017 S. Platte Basin Reservoir Storage: 107% of Average

That matches well with what I remember. I logged my surf days last year, along with river flows, and these are the early days I got out to RRP:

3/24 600 cfs rain bump
3/27 100 cfs
3/29 100 cfs
4/14 100 cfs
4/15 100 cfs
5/12 197 cfs

May 12, 2017  was basically the beginning of the season in earnest. 100 cfs or so is enough to get a slow ride on chiclets, but you need 200 or so to get a good ride on Benny’s. Let’s compare that to a similar date range in past years, from April 1 to August 1, along with their respective snow packs. I’ll start with the snow first, since it’s where we get the flow…

2016 River Run Park Flows

April 1 Chatfield Storage: 27,234 Acre Feet

S. Platte Basin Reservoir Storage: 105% of Average

A little earlier start, with flows rising more steadily through April. Moving back…


2015 River Run Park Flows

April 1 Chatfield Storage: 27,034 Acre Feet

S. Platte Basin Reservoir Storage: 117% of Average

More like 2017 than 2016, with flows staying pretty low aside from the occasional rain/snow spike until the very end of April/beginning of May, but then they went nuts. Seems out of character for the snow pack.


2014 River Run Park Flows

April 1 Chatfield Storage: 27,344 Acre Feet

S. Platte Basin Reservoir Storage: 112% of Average

Another variation, it looks like 2014 saw a spike in flows for the second half of April, followed by things falling off and getting spotty in May, with steadier flows in the second half of May and into June. Overall, a pretty decent year.


2013 River Run Park Flows

April 1 Chatfield Storage: 27,414 Acre Feet

S. Platte Basin Reservoir Storage: 87% of Average

An uneven low water year, without much in the way of flows over 200 cfs. This was a drought year. Can’t end on that note, so let’s pull 2012:

2012 River Run Park Flows

April 1 Chatfield Storage: 27,118 Acre Feet

S. Platte Basin Reservoir Storage: 112% of Average

Ug. I don’t want to talk about this one. One more:

2011 River Run Park Flows

April 1 Chatfield Storage: 26,316 Acre Feet

S. Platte Basin Reservoir Storage: 106% of Average

Unusual, compared to the others; the flows turned on but they didn’t do so until the second half of June.

So When?

In most years, flows turn on (>200 cfs) at River Run sometime between late April and mid-May, but there are a lot of outliers. This year’s snowpack isn’t looking as dire as it did earlier in the year, but it’s still below average. I have more information on the snowpack over here. And I should be able to update that information in the coming months; early April tends to be our peak snowpack depth of the season.

Generally though, this is how our snowpack is looking:

This is how it compares to past years:

The legend is a little tough to read; Red = Average, Green = 2015, Yellow = 2016, Blue = 2017, and Purple = 2018

And this is how our reservoir storage is looking compared to average. Way better than I expected, frankly, though it’s tough to compare to earlier years since they didn’t make these pretty graphs before 2014. And Chatfield’s data is kept by NOAA, which isn’t as big on data analysis as the USGS.

Current Chatfield storage is 24,531 acre feet. Low, compared to past historic years, but in line with last year. I think that has more to do with water level controls than anything else.

S. Platte Basin Reservoir Storage: 110% of Average as of 3/29/18. Overall, this doesn’t seem to have a particularly strong correlation with river flows if it’s near average.

Here are the current USGS forecasts for the South Platte basin. They don’t look outstanding, but note that the S. Platte forecast in particular does not account for any reservoir flows. Even they don’t know what’s going to happen there. Makes me feel better about our inability to figure out what is going to happen at Chatfield at any given time:

April Update

Here are the current snowpack levels as of April 10, 2018. The northern half of the state continues to improve with the recent storms, while the southern half of the state continues to be dry. Another storm forecast for this coming weekend also looks to favor the northern mountains:

Water Temperature

Finally, a word on water temperature and insulation. This time of year I tend to wear a Kokatat GMER drysuit, but I have it from kayaking and they’re expensive. Nice to have fuzzy socks at the end of a surf though.

If you’re in a wetsuit or need one, here is a decent guide to options. Generally, this is a breakdown of water temperatures and the level of insulation you want, though everyone is different:

Temp, F:

75+:  Board shorts, rashguard. No wetsuit needed

75-63:  2mm Top or Shorty (short-sleeved suit)

58-64:  3/2, maybe long sleeve springsuit

55-60:  3/2mm full suit, booties

48-55:  4/3mm, booties

43-48:  5/4mm, booties, hood; maybe 4/3 if well-sealed

<43 6/5 or 5/4:  booties, hood, or drysuit

A number of the USGS gauges have thermometers on them as well. Here are the water temps just downstream of RRP last year:

Note the big daily variations due to the shallow riverbed. Dawn patrol water temps are usually 10 degrees colder than they are at sunset. And we start to see a significant warm up in May or so, with water temps climbing into August.

Finally, pay attention to the flows. Though RRP may not run for a couple weeks or a month, there are other surfable waves on the front range that will turn on earlier with less water. And if you want notifications when the water finally does show up, I cover how to set those up here.