Case: After a deadly landslide in Columbia, more than 1000 soldiers, policemen, and rescue workers are searching survivors after more than 200 people died on Saturday. The cause of this landslide was heavy rainfall in the city of Mocoa. The army said in a statement that in addition to the 200 dead there were also more than 400 injured. There are conflicting reports however, as the local media report 300 dead while the red cross reports 200 dead. The Colombian air force is working on getting supplies into the area to help survivors. There is a real issue because power lines have been cut and so has water, and local residents have reported that they have resorted to drinking rainwater.
Analysis: Heavy rainfall was the cause of this deadly landslide. More than a third of the regions monthly rainfall occurred in one evening. This caused the river to burst its banks and over-saturated the soil, causing it to liquefy and flow, leading to the landslide. To make maters worse, the debris flow was so fast that it carried many heavy objects with it, including lorries, which likely lead to a higher death toll. The heaviest rainfall was also during the night, which likely lead to the death toll being higher, as people were asleep when the flows hit their homes.
Conclusion: This area is known for having heavy rainfall, and in the last few months it, and surrounding regions had landslides. For example, just a month ago, in the town of Medellin, less than 500 km away, 9 people were killed by a landslide. Furthermore, as I reported in another of my posts, Peru which neighbors Columbia, had its own heavy rainfall and devastating landslides. Knowing all this, Columbia should have been much better prepared for this. They saw what happened in Peru just a few weeks ago and should have evacuated residents close to the river and built flood defenses if they could. Furthermore there is quite a lack of communication and as the BBC reports, its hard to get verified reports as rescue operations have only really now begun in earnest. Another grave concern is that residents are resorting to drinking rain water, the government should have provided residents with water purifiers or water purification tablets, which literally cost less than a dollar a piece, and would save lives. Finally, the fact that the air force has to bring in supplies shows that the town itself has no emergency supplies stored.
A mudslide occurred overnight in Bogata, Colombia. The mudslide was caused by, “Sudden, heavy rainstorm happened around midnight in Mocoa, a provincial capital of about 40,000 tucked between mountains near Colombia’s southern border with Ecuador.” Three rivers burst their banks and sent muddy water rushing through the town in the middle of the night sweeping away houses and uprooting trees. It also carried larger rocks and sediment surging down the mountain toward the town. “Many residents did not have enough time to flee. An avalanche of water from three overflowing rivers tore through a small city in Colombia while people slept, destroying homes, sweeping away cars and killing at least 193 unsuspecting residents.” The red cross says that 202 people are injured and 220 people are missing. The president of Columbia has declared a state of emergency. They are still looking so the death toll will probably rise.
Introduction: After days of heavy rain and strong winds in Ghana, the soil had become quite saturated with water and much more susceptible to mass wasting. As a result of these two factors, trees surrounding kitampo waterfall were not anchored securely into the ground. When there was a stronger updraft of wind, the trees broke free of the ground and were carried into the water and down the waterfall. These trees unexpectedly falling caused the deaths of the 20 teenagers.
Background: Normally trees are quite capable of holding themselves securely in the ground, and we rarely look at trees and expect them to fall at any minute. However, when there is a lot of rainfall, the soil becomes saturated with water and does not hold itself together as well. Now let us imagine a day old baguette, its super hard, but when you soak it in water for a couple hours, it becomes soggy and falls apart at the slightest touch, the same goes for the soil and the trees in it. It would not take a lot of wind to move these trees out of the soil and carry it with it.
Analysis: This waterfall is frequented often by locals who wish to cool off from the heat by lounging under the waterfall. However, the locals should have been educated better about the hazards associated with days of heavy rain as well as strong winds. Both these factors result in increased risk of mass wasting, flooding, and other dangers. As a result, the government should have warned about the increased risk level with being under the waterfall. Going forward, the government should educate about these dangers and post signs at this waterfall and other waterfalls across the country warning people not to use the river after days of heavy rain and or during strong winds.
Unusually high temperatures in the Pacific Ocean are to blame for the latest flooding in Peru. It is some of the worst flooding in recent history. Killing and estimated 12 people, sweeping away vehicles and homes. This flooding comes after a serious drought and has completely caught the authorities by surprise. It has been raining the last three days, causing numerous rivers to burst their banks and subsequently causing mudslides. This is not the first such event this year, since January there have been 62 deaths, 11 missing and 12,000 destroyed homes. A local weather expert was interviewed and stated that these were highly unusual weather conditions and that the ocean was 5-6 degrees Celsius warmer than it would normally be. Peru was also ravaged by wildfires in November of last year, burning 12,000 hectares of land.
Because of global trends in rising temperatures there have been many documented cases where weather has been unpredictable or weather events were much stronger than they had been in the past. This was probably the reason for the wildfires in November as the warmer temperatures caused there to be dryer conditions and lead to a higher risk of fire, and these same warm temperatures then caused the storms to much more powerful as they draw their energy from warm water.
Global warming is likely to blame for both these events as higher temperatures have caused more stronger, more unpredictable weather events. However, the Peruvian authorities should have been on higher alert following the wildfires, because as we discussed in class, wildfires are a chemical process, and these fires definitely contributed to the flooding. Either by burning away vegetation which held the soil together, or making the soil itself impermeable, leading to runoff and more mass wasting. The best thing they could have done was to raise awareness about the heightened risk, and have communities have plans ready following the wildfires, in case there would be mass wasting and heavy rains following the drought.
Another avalanche occurred at the ski resort in Tinges, France this morning. This is the second avalanche another avalanche occurred last month at the same ski resort and killed 4 people. Luckily no one was killed this time even though the avalanche passed through a blue intermediate slope that is popular for families. Some people were buried by the avalanche but they were rescued. The avalanche risk posted that morning was a 4 out 5.
Heavy rains have flooded a lake in Sarejevo, Bosnia; roughly 150 people have been evacuated and a major highway has been flooded. The lake itself is only about a week old; it was created when a massive landslide of mine waste from a mining pit poured into a river. The closure of the highway has been a large problem for Bosnians, as it is a major route from the capital of Sarajevo to other towns; in addition, it is feared that the flooding will continue to worsen. Work crews are attempting to lessen the danger of this by draining the lake into drainage ducts. The 150 people who were evacuated were evacuated from the villages of Ribnica and Mramor; in both of these villages, the houses and buildings have been entirely swept away. While authorities have stated that the citizens will be economically compensated for the damage, the villages have been so decimated by the landslides and the flooding it is expected that people will never be able to return to these locations.
It can be noted how in this case, one hazard made it possible for another to occur; without the lake that was created by the landslide, the heavy rains would most likely not have caused such severe flooding.
There are currently heavy rains in California, with meteorologists predicting the strongest storms in years to hit the south. The current rains in California are just the beginning of a dangerous atmospheric river which will hit the state. The storm is massive, stretching out over the Pacific. the forecast is that it will arrive Friday and last into Saturday. Flood warnings are in place for streams and creeks and there is a high wind warning for gusts up to 70 mph. Rainfall predictions range from 2-6 inches of rain. With the soil already being saturated from a particularly wet season, there are concerns that there will be flash flooding as well as debris flows. Furthermore, heavy snows are expected in the mountains and officials are keeping a nervous eye on the Oroville dam which already had its fair share of issues earlier this week.
An avalanche struck in the French Alps at 6,900 feet in elevation off the ski runs killing four at a popular resort. Another avalanche occurred in Garfield County, Colorado killing a skier and injuring others. The natural disaster took place a few miles south of Vaughn Lake in a wilderness area in the remote back country.
Here are articles with details on the avalanche in France:
And an article about the avalanche in Colorado:
“At least 156 people have died along the Afghan-Pakistani border after three days of heavy snowfall caused a series of deadly avalanches Sunday.”
The death toll is expected to rise, as the National Disaster Management Authority says that more people are still trapped under the snow. Over 300 civilian homes have been destroyed, and most of the victims so far are women and children.
Evacuation efforts, however, are just being implemented two days after the series of avalanches.
California experienced serious travel problems as heavy rain swept across the state. Multiple major roadways were shut down due mudslides. There were multiple motorists who had to be rescued after they had consciously avoided road barriers and driven into flooded roadways. One truck was even hit by a mudslide and flipped over. The Bay Area was hit hardest by the mudslides.
Mudslides shut down roads across California, including the corner of Redwood Road and Browns Valley Road in Napa County on February 7, 2017. (Photo/Twitter/@CountyofNapa)