We have stopped issuing regularly scheduled advisories for the 2011-12 season. We will be monitoring the weather through May, and update this Statewide product as necessary. We will keep the Field Reports up to date.  We will resume regularly scheduled products on or about November 1, 2011 as conditions warrant.

Even though we are not issuing advisories, we are still collecting information. Please send us your observations and we'll keep the list of Field Reports and Avalanches current

If you're headed into the high country use our Weather Stations by Zone page to check the overnight low temperatures for the last few days. You can also check stream flows (Colorado DWR, USGS) to see how much water is draining through the snowpack and into the rivers and creeks. Remember there is a lag between melt and measured runoff. You can use our Weather Stations by Zone page to monitor past and present weather conditions too

There have been avalanche accidents in Colorado every month of the year. Avalanches in the spring and summer are less frequent than in mid winter. This means you can let your guard down a little bit, but not drop it completely.

In the spring the snowpack transitions from a cold, multi-layered snowpack to one that is isothermal (one temperature) and with uniform grain types throughout. This occurs as melt water percolates into the dry snowpack. The snow is weakest the first time water hits a dry layer and also when the snow becomes completely saturated.This transition occurs at different times on different slopes. You will see it begin on low-elevation southerly aspects first and last on high-elevation northerly aspects.

The amount of free water running through the snowpack is an important factor in determining the snow stability. This will change throughout a day and over the course of a week depending on the weather. Although we are not issuing weather forecasts during the summer you can still get good weather forecasts from the National Weather Service. There are also some tools you can use to figure out what has been happening over the last few days.

The first is overnight temperatures. Cold temperatures allow the snowpack to re-freeze. It will be strong in the early mornings, allowing for fast, safe travel. Climb when it's cold, and descend as the snow softens. Our list of Weather Stations by Zone will help you determine the overnight temperatures.
•    Recent snow can become weak after one or two nights without a freeze.
•    Summer snow can become weak after two, three, or more nights without a re-freeze.

The second is stream flows. As melt water drains out of the steep snow slopes it flows into the streams. Check  (Colorado DWR, USGS) the level of the streams in the area you plan to travel and look at the trend over the last few days. Remember there is a lag between melt on an alpine slope and a reading at a low elevation stream gauge.  

Once you are out in the backcountry watch the snow and make sure you are down in the low lands before the snow becomes wet and weak. You can determine how strong the surface snow is by how deep your boots penetrate into the snowpack. Use a boot that is not attached to other equipment for this assessment.
•    Boots stay on the surface and the snow is frozen or just starting to soften. Keep climbing or wait just a bit before you descend.
•    Boots sink to your ankles means it is time to descend. The surface snow is starting loose strength.
•    Boots sink to your calves and you are getting red flags from the snowpack. Choose a route that avoids descending steep slopes, and avoid crossing under them.
•    Boots sink to your knees and you are getting flashing lights and sirens. It is past time to get off of and out from under steep slopes. Bare ridges and shallow slopes are your safest options for routes.

Overhanging cornices should be suspect any time the snow is soft. They can give way with little warning, and might be sufficient to trigger avalanches on the snow fields below. If you are climbing routes with overhanging cornices or contemplating hucking a cornice, make sure you are there while the core of the cornice is still cold and strong. Remember that cornices may see the sun much earlier than the snowfields below them. In general cornices are dangerous structures and should be avoided.

It helps to know the micro-topography of routes before you ascend or descend. A shaded couloir may have frozen, strong snow, but could have avalanches running down it from sunny snowfields above. Careful perusal of maps and guidebooks can be of great benefit.

Constantly monitor the condition of the snow surface. Remember that slopes above you can be much sunnier, and there-for weaker than the snow you are on. The snow can quickly switch from supportable, strong corn to weak slush.

From all of us here at the CAIC, thank you for your support and your observations. Have a safe and enjoyable summer and we’ll be back next fal