Times are a changing. The weather is changing. Big Thompson Canyon, on the Front Range, got slammed by 13 inches of rain one night in 1976, reducing much of the highway that ran through it to debris in the streambed, an event considered a once-in-a-thousand-year occurrence. This year, the area was swamped by several days of heavy rain, and once again, much of the highway washed downstream – another thousand-year storm. My, how time flies! Extremes once considered very rare are popping up more and more.
Welcome to the new normal. Expect weather extremes and expensive ones; welcome to the future.
There are some incredible things occurring to planet Earth’s systems, creating all sorts of extremes: Hotter weather, colder weather, drier weather, more severe storms, stronger winds, devastating wildfires, blinding dust storms. The events are all related.
Overall, the planet is warming. Yes, there are blips once in a while, but the overall trend is still up. Extremes are way up.
Heat energy is required for water to evaporate. Most of this energy comes from the sun. This energy is stored in the water vapor, and is known as the “latent heat of water.” This “stored heat” cannot be felt until it is released by another change of state – condensation – back into liquid water or a solid such as hail, sleet or snow. Heat energy is transferred to an air parcel as the water vapor condenses or freezes. This makes the air parcel warmer and causes it to rise faster. About 540 calories of energy are released as a single gram of water condenses! When each gram freezes, an additional 80 calories is released. This released heat energy drives storms.
Warmer air can hold more water, increasing exponentially as the temperature rises.
Just a little increase in air temperature makes a huge difference in the potential water available in the atmosphere. This increase in moisture will come back to earth as more rain, hail or snow. At the same time, if the air has far less of the amount of moisture it could hold (drier air) then little or no moisture will precipitate, and that air has a greater capacity for sucking more moisture up. Bring on the droughts, too!
Jet streams are rivers of air that in these latitudes flow mostly west to east in a rather straight pattern, and push storms and weather systems across the continents west to east. Because temperatures have increased more in far north latitudes than in mid-latitudes the jet stream has slowed and now often “wobbles,” making severe bends north and south, and often gets “stuck” in these wobbly patterns and doesn’t move much. This creates cut off lows and blocking highs and weather systems that don’t move. Combine this with masses of dry air or moisture and you have the set up for droughts and terrible dust storms such as hit eastern Colorado this year, as well as massive storm systems and related huge floods, such as hit the front range in mid-September.
These “stuck” jet stream patterns often vary where they get stuck from year to year. Thus, causing opposite extremes to the same location on different years. For a great educational video on this, go to: www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2432 and scroll down to Video 1 and watch it. It’s an excellent explanation.
We have a new term in meteorology – the “Supercell” storm. Supercell storms tend to last much longer than typical thunderstorms, are more powerful, often have far more rain and more or larger hail, and sometimes tornadoes. The rainfall is far greater all over the entire country now. Over the past century, the amount of rain falling in heavy storms increased by 22 percent for the U.S. on average and 31 percent in the Midwest.
A recent article in Science News was titled “Dirty air fosters precipitation extremes – Changes to clouds encourage drought in dry areas and torrential downpours in moist ones” points out research that shows aerosol pollution, such as is emitted by coal-fired power plants and diesel exhaust have the ability to powerfully affect rainfall. The probability of heavy rain is increased by 50 percent from clean to dirty conditions, whereas the chance of light rain is reduced by 50 percent.”
Severe storms are getting more common every year, along with more, and larger, hail. Insurance claims resulting from hailstorm damage increased 84 percent in 2012 from their 2010 level. In many areas now, instead of roof damage deductibles being $500 or $1,000, they are a percentage of your home’s overall insured value. Thus, the hail damage deductible for a $300,000 home might now be in the $9,000 range. Ouch!
Expect increasing rates every year. The Colorado Division of Insurance has been reporting recent filings by homeowners’ insurers that reflect about a 15 percent overall increase in premiums.
In many areas now, some “standard market” insurance companies are refusing to even write new policies, forcing customers to the (more expensive and sometimes less reliable) “substandard market.”
The CEO of Swiss Re Americas, J. Eric Smith, said in a talk in New York City in July “What keeps us up at night is climate change. We see the long-term effect of climate change on society, and it really frightens us.”
We live in an area that has increasing wildfire potential (caused by dry weather and people living close to or in forests) and increasing severe storm potential with large hail and heavy rains, and as we have mountains with steep slopes and narrow canyons, we’ll see more floods and debris flows. Smart folks will learn more about geology, meteorology, and environmental systems – and make adjustments accordingly.
Life in Southwest Colorado has its great benefits. But life is full of trade-offs, too. Hang onto your wallets! And, welcome to the new normal.
Bob Thompson is a retired college and university professor who specialized in Earth systems. He lives at Vallecito. Reach him at firstname.lastname@example.org.