Sunday, February 24, 2019
Saturday, February 23, 2019
Tuesday, February 19, 2019
Scientists Warn Rare "Atmospheric River" Storm in LA Could Cause Catastrophic Damage
News Link
Storm in 1862 dropped 36" of rain on LA over a 45 day period. A similar storm would overtop and collapse the Whittier Narrows Dam and cause an estimated $750 billion in damages downstream.
This story highlights the problems with traditional statistical methods used to forecast rare storms. As a young engineer, I worked on the National Flood Insurance Program in Minnesota running the first hydrologic models to determine the 100 year flood plain in the 1970s. At that time, many of the small towns in Minnesota had only 30 or 40 years of weather data to forecast what the 100 year flood would be. It was done with total linear thinking, using a standard statistical analysis that assumed the 30 or 40 years worth of data was typical of the past 500 years and can be used to forecast the next 500 years. Not only is that assumption wrong but the entire presentation of the average condition (called normal) and the "once in 100 year flood" are completely misleading and incorrect. The average or normal is a rainfall or temperature that only happens 1 time in 100 with about 50% the time being lower and 50% higher. The bell curve shows the probability of a rainfall event expressed as the percent chance it will occur in any given year. The 100 year flood is the flood that has a 1% chance of happening next year, not the flood that happens once every 100 years. In rare circumstances the "100 year flood" can happen 2 years in a row or may not happen for 200 years. The only way to determine long term hydrologic cycles is the study of tree ring data correlated with river levels.
This same problem of linear thinking plagues the attempts to predict global warming and is one of the reasons that models predicting temperature changes since the 1990's have not been accurate.
Storm in 1862 dropped 36" of rain on LA over a 45 day period. A similar storm would overtop and collapse the Whittier Narrows Dam and cause an estimated $750 billion in damages downstream.
This story highlights the problems with traditional statistical methods used to forecast rare storms. As a young engineer, I worked on the National Flood Insurance Program in Minnesota running the first hydrologic models to determine the 100 year flood plain in the 1970s. At that time, many of the small towns in Minnesota had only 30 or 40 years of weather data to forecast what the 100 year flood would be. It was done with total linear thinking, using a standard statistical analysis that assumed the 30 or 40 years worth of data was typical of the past 500 years and can be used to forecast the next 500 years. Not only is that assumption wrong but the entire presentation of the average condition (called normal) and the "once in 100 year flood" are completely misleading and incorrect. The average or normal is a rainfall or temperature that only happens 1 time in 100 with about 50% the time being lower and 50% higher. The bell curve shows the probability of a rainfall event expressed as the percent chance it will occur in any given year. The 100 year flood is the flood that has a 1% chance of happening next year, not the flood that happens once every 100 years. In rare circumstances the "100 year flood" can happen 2 years in a row or may not happen for 200 years. The only way to determine long term hydrologic cycles is the study of tree ring data correlated with river levels.
This same problem of linear thinking plagues the attempts to predict global warming and is one of the reasons that models predicting temperature changes since the 1990's have not been accurate.
Tuesday, February 12, 2019
Saturday, February 9, 2019
Conservationist Studies Mountain Lion Behavior with 30 Trail Cameras
News Link
Observes that mountain lion attacks are rare and the few that do are when the mountain lion does not recognize you as human. That is certainly the case for juvenile mountain lions that have either a genetic defect or its mom didn't train it enough or correctly to differentiate people from prey. In my mind, recognition of people is a learned trait reinforced by bad experiences that is handed down from one generation of mountain lions to the next. I am pretty sure if humans were passive and docile when attacked that mountain lions would happily make people part of their diet. There have been a few cases where mountain lion attacks have happened when hikers have stumbled upon a cat eating a deer. These are mature mountain lions that would otherwise avoid people and attack to protect their food stash.
Friday, February 8, 2019
Cold Weather Causes Major Natural Gas Line in Summit County to Lose Pressure
News Link
The line is owned by XCEL. XCEL responded with rolling blackouts to force a reduction in gas usage for heating (furnaces require electricity to operate). Service was cut to 15,000 customers and shut down the lifts at Breckenridge and Keystone.
Thursday, February 7, 2019
Wednesday, February 6, 2019
Details of Man's Fight With Mountain Lion Amazing!
News Link
The link to the Denver Post has a paywall so I'll try and recap.
The best recap I can come up with is think tiger attacks unarmed gladiator in the Colosseum.
The man was running on a trail and the juvenile mountain lion approached him from behind as cougars do with all prey. The runner faced the cougar and did all the right things, yelling and putting his hands over his head to look big but the cat attacked anyway. It may have looked something like this
Video
The cat jumped on him and tried to secure him as they do with all their prey by trying to clamp down on his neck. The man blocked the cat with his forearm and the cat clamped down on the forearm. The wrestling match to the death began. The man reached out with his free hand, grabbed a rock and pummeled the cat's head but the cat hung on to his forearm. The fierce wrestling continued and the runner managed to take his free arm and put the cat in a headlock. The headlock eventually forced the cat to release his forearm and the man quickly reversed his position to get on top of the cat and put a double arm chokehold on its neck and double leg hold on its body. Squeezing with all his might, the cat was suffocated.
What a story! It will be interesting to see if this man has a wrestling background or just instinctively knew what to do.
Just remember you saw it here first when the news stories start reporting it this way.
The link to the Denver Post has a paywall so I'll try and recap.
The best recap I can come up with is think tiger attacks unarmed gladiator in the Colosseum.
The man was running on a trail and the juvenile mountain lion approached him from behind as cougars do with all prey. The runner faced the cougar and did all the right things, yelling and putting his hands over his head to look big but the cat attacked anyway. It may have looked something like this
Video
The cat jumped on him and tried to secure him as they do with all their prey by trying to clamp down on his neck. The man blocked the cat with his forearm and the cat clamped down on the forearm. The wrestling match to the death began. The man reached out with his free hand, grabbed a rock and pummeled the cat's head but the cat hung on to his forearm. The fierce wrestling continued and the runner managed to take his free arm and put the cat in a headlock. The headlock eventually forced the cat to release his forearm and the man quickly reversed his position to get on top of the cat and put a double arm chokehold on its neck and double leg hold on its body. Squeezing with all his might, the cat was suffocated.
What a story! It will be interesting to see if this man has a wrestling background or just instinctively knew what to do.
Just remember you saw it here first when the news stories start reporting it this way.
Tuesday, February 5, 2019
Trail Runner in Fort Collins Attacked by Mountain Lion, Fights Back and Kills Mountain Lion
News Link
An incredible story - hearing the details from the man attacked will be interesting. Mountain lion attacks are very rare in Colorado. Fighting back has saved the life of attack victims in the past but killing the mountain lion bare-handed has to be a first. This attack is consistent with most of the attacks that have happened in the past. A very small percentage of juvenile mountain lions that have just gone out on their own to establish its' territory gets it terribly wrong on their food source.
An incredible story - hearing the details from the man attacked will be interesting. Mountain lion attacks are very rare in Colorado. Fighting back has saved the life of attack victims in the past but killing the mountain lion bare-handed has to be a first. This attack is consistent with most of the attacks that have happened in the past. A very small percentage of juvenile mountain lions that have just gone out on their own to establish its' territory gets it terribly wrong on their food source.
Sunday, February 3, 2019
Saturday, February 2, 2019
Friday, February 1, 2019
Subscribe to:
Posts (Atom)