“Weather collector Bob” unveils real truths about local fire conditions
~ Bob Volpe ~
We’ve all heard the Colorado weather adages, “If you don’t like the weather, stick around for 15 minutes.”
And whether we like it or not,“March and April are our snowiest months.”
While there is a certain degree of truth in those sayings, you can’t plan a barbecue around them. This past winter may have seemed like an especially dry year when it comes to snowfall and there is already talk of a potentially severe fire season. Looking back on snowfall records over the last 12 years, however, this season’s snowfall is not that far from normal.
In collecting snowfall records at my house in Woodland Park since 2005, I was surprised to find that March doesn’t always live up to the reputation of being one of the snowiest months.
The average snowfall over the last 12 years is 100 inches , recorded at my house in Woodland Park. The average snow for the month of March since 2005 is 14.5 inches.
But in comparing snowfall averages over the last 12 years between March and April, April wins out as the month for the most snowfall recorded, with an average of 23 inches. In 2011 there was no snow in the entire month of March, and April only brought in 18 inches. In fact, the total snowfall for the 2011 year was 97 inches, which is only 3 inches shy of the 12 year average.
The fallacy of comparing dry weather with wildfire threats
According to Wikipedia there were no significant wildfires during the 2011 snow season, which was a low snowfall year for both March and
April in our area. The snowfall recorded n 2012 when the Waldo Canyon fire raged during a low moisture year with only 72 inches. That fire was determined to be an arson event, but drought conditions in that area were a big factor in the severity of the fire, as were strong dry winds.
The following year when the Black Forest fire burned was just short of the average at 92 inches of total snow. That fire was determined to be human caused and arson was expected, but never proven. While I do not have local snowfall records for the 2002 season when the Hayman Fire burned, after talking to NETCFPD fire fighter Jonas Johnson, 2002 was indeed a severe drought year. The total snowfall in Woodland Park since 2011 has fluctuated from slightly below average for 2011, 2012, and 2013 to above average in 2014 and 2015. This year’s snowfall has been significantly below average for this time of year at a mere 58 inches to date, but we have the rest of April and May to make up for lost snow. It was interesting to compare seasonal snowfall with the outbreaks of wildfires that corresponded with seasonal snowfall. However, attempting to extrapolate wildfire risk using these numbers collected in Woodland Park would be flawed, since snowfall varies widely over the Front Range.
The trend since 2005 has been cyclical, with slightly below average snow to above average snowfall, with only a few years being either well above or well below. For instance last year we received 40 inch of snow in March and in 2011 we received nothing in March.
The Meaning of the Weather Reports
What all this means in terms of seasonal snowfall as a predictor for wildfire danger in our area cannot be predicted accurately, as there
are too many variables to just use snowfall as an indicator. Severe drought conditions are also an important factor, as was the case in
2002 when the Hayman Fire occurred.
There are a number of other factors that make for dangerous wildfire conditions. According the National Park Service, “There are many
system and schemes that attempt to provide accurate and reliable predictions of fire danger that analyze the fuel, topography, and
weather, and integrate their effects into a set of numbers that fire managers can use to meet his or her needs. Relative humidity, dead
fuel moisture, live fuel moisture, and dry winds, are a few factors that contribute to elevated fire risk.”
The Park Service uses a formula to estimate fire danger called the Haines Index. This is computed from the morning soundings from
Radiosonde Observation (RAOB) stations across North America. The index is composed of a stability term and a moisture term. The stability
term is derived from the temperature difference at two atmosphere levels. The moisture term is derived from the dew point depression at
a single atmosphere level.
This index has been shown to correlate with large fire growth on initiating and existing fires where surface winds do not dominate fire
behavior. Haines Indexes range from 2 to 6 for indicating potential for large fire growth.
The Rocky Mt Coordination Center, based in Lakewood, CO. is an organization that tracks wildfire conditions and reports risks to fire
districts throughout the region. They offer insight and predict conditions of fire risk, rating those risks as above normal, normal,
and below normal. Their extended outlook for June through July of this year suggest a below normal risk in the mountains and a normal risk
for the front range of Colorado.
The National Weather Service (NWS) also reports and predicts on weather conditions that can be a significant factor in wildfire
conditions. Their temperature predictions for this summer are that there is a 40 percent chance of above normal temperatures and normal
precipitation for Colorado through the summer. While normal precipitation is an encouraging prediction, the NWS is also predicting continuing drought conditions for much of the eastern plains and the Front Range through June of this year. This may seem to be contradictory to their precipitation prediction, but normal precipitation does not bust a drought.
As the data from my own record keeping and the risk potential predictions from both the NWS and The Rocky Mt Coordination Center
indicate, we are experiencing a low snowfall year, by historic standards, but this is not shaping up to be an extreme situation.
Never forget the immortal words of our friend Smokey the Bear, “Only you can prevent wildfires.”