Falling Trees Can Cause Property Damage, Injury or Death

During and after large storms, especially those with high winds, there are always reports of fallen trees and tree limbs, which can cause injury or death to those who are in the wrong place at the wrong time. In the past few months in California alone, a woman was killed by a falling tree in the San Francisco Bay area on Jan. 9; another woman was struck and killed by a falling tree while walking on a golf course in the Bay area on Jan. 8; and the mother of a bride was killed when a tree fell on a wedding party in Southern California on Dec. 19. In New York City’s Bryant Park, a woman was killed and five people were injured when a massive tree snapped in half on Sept. 4, 2015.

Falling trees are also a major cause of property damage. If winds are strong enough, even healthy trees can be uprooted or broken, according to the Tree Care Industry Association (TCIA).

It might not take a storm or high winds to cause a cracked or rotted tree to fail under its own weight, however. Cracks are hazardous because they compromise the structure of the tree and can eventually split the stem in two. Cracks are particularly dangerous when combined with internal decay, according to the TCIA, thus the presence of multiple cracks and decay indicates a potentially hazardous tree.

Property owners should be concerned about trees falling, especially if cracks are evident. “While trees are genetically designed to withstand storms, all trees can fail – and defective trees fail sooner than healthy trees,” Tchukki Andersen, staff arborist at TCIA, said in a statement. “To a professional arborist, certain defects are indicators that a tree has an increased potential to fail.”

Cracks in tree trunks can be one of the major indicators of an unstable tree. Most cracks are caused by improper closure of wounds or by the splitting of weak branch unions. Cracks can be found in branches, stems or roots, and vary in type and severity:

  • Horizontal and vertical cracks run across the grain of the wood and develop just before the tree fails, making them very difficult to detect. Vertical cracks run with the wood grain along the length of the tree and may appear as shear or ribbed cracks.
  • Shear cracks can run completely through the stem and separate it into two halves. As the tree bends and sways in the wind, one half of the stem slides over the other, elongating the crack. Eventually the enlarging crack causes the two halves of the stem to shear apart.
  • Ribbed cracks are created as the tree attempts to seal over a wound. Margins of the crack meet and mesh but are reopened due to tree movement or extremely cold temperatures.
  • Thicker annual rings are created in order to stabilize the developing crack at the location of the wound. This forms the ribbed appearance over a period of many years.

To prevent damage, TCIA recommends having trees examined by a qualified arborist to determine the potential for failure. An expert will measure the shell thickness in a few locations around a tree’s circumference, determine the width of the crack opening and check for any other defects.

Weather Threatens Oroville Dam Emergency Efforts

As measures are taken to repair a damaged spillway at the Oroville Dam in Northern California, weather forecasters are calling for rain later this week. Almost 200,000 people were evacuated from their homes below the dam, the largest in the country, on Feb. 12 as erosion of the dam’s emergency spillway threatened to flood the towns below.

While the situation was said to have stabilized on Sunday morning, conditions worsened and evacuation orders were issued. Roads in the area quickly backed up as a result, according to reports.

The dam’s main spillway was damaged after a winter season of record rains and snows following years of drought in the state.

Photo: California Department of Water Resources

California Representative John Garamendi told MSNBC that the evacuation was essential. “Fortunately when they were able to open the main spillway gates. That began to lower the reservoir level, because the water coming into the reservoir was about half of what they were able to expel down the main spillway, so it’s stabilized.”

The next issue, he said, is whether the spillway can be patched up “sufficiently to weather the storms that are clearly ahead of us.” Garamendi added that the months of March and April are the heavy storm season in the state.

Sheriff Kory Honea of Butte County said at a press conference that the Department of Water Resources (DWR) reported that the dam’s erosion is not advancing as rapidly as they thought. He said a plan is in place to plug the hole in the spillway by dropping large bags of rocks by helicopter. The DWR said that another measure being taken to relieve pressure on the spillway has been to raise the rate of discharge water from 55,000 cubic feet per second to 100,000 cfs, which it said has been working.

Helicopters transport large bags of rocks from the Oroville Dam parking lot, to the erosion site at the Oroville Dam auxiliary spillway in California, to help fight further erosion, February 13, 2017. Oroville is in Butte County. Florence Low / California Department of Water Resources

The New York Times reported that Northern California is close to 225% above normal rainfall levels since Oct. 1. According to the Times:

Repeated rounds of rain have pounded the area in recent weeks, rapidly raising the water level at Lake Oroville, the second-largest reservoir in California and a linchpin of the state’s water system. On Tuesday, a gaping hole opened in the main spillway that is used to release extra water. Early Saturday, an adjacent emergency spillway was also put into use, the first time water flowed over it since the dam was finished in 1968, department officials said.

State officials have said the 770-foot Oroville Dam itself, the nation’s tallest, is sound.

The problems with Oroville Dam are not a surprise to some. In 2005, during a relicensing process for the dam, three environmental groups warned the DWR of potential dangers with the emergency spillway, which is not a concrete spillway, but a concrete lip with a dirt hillside below. The concern was that the hillside could be easily eroded in the case of an emergency.

The Washington Post reported:

The upgrade would have cost millions of dollars and no one wanted to foot the bill, said Ronald Stork, senior policy advocate for Friends of the River, one of the groups that filed the motion.

“When the dam is overfull, water goes over that weir and down the hillside, taking much of the hillside with it,” Stork told The Washington Post. “That causes huge amounts of havoc. There’s roads, there’s transmission lines, power lines that are potentially in the way of that water going down that auxiliary spillway.”

Federal officials, however, determined that nothing was wrong and the emergency spillway, which can handle 350,000 cubic feet of water per second, “would perform as designed” and sediment resulting from erosion would be insignificant, according to a July 2006 memo from John Onderdonk, then a senior civil engineer for the Federal Energy Regulatory Commission.

Garamendi said that “What happened with the widening of the sinkhole was the result of someone overlooking the problems, including the fact that there was no concrete apron on the spillway.”

He also noted that while there will most likely be federal dollars to help rebuild the dam, “This is just one really startling, quite tragic and potentially catastrophic example of what’s happened to the infrastructure across America. We’ve seen bridges collapse in Minnesota, we’ve seen them on I-5 in Washington State and now this reservoir, which is the linchpin of California’s water system.”

Flood, Wind Dominant Natural Hazards in 2016

While most natural hazards occurring in the United States last year saw average or below average activity, the exceptions were flood and wind, according to the CoreLogic report Natural Hazard Risk Summary and Analysis, released today.

Severe flood events driven by substantial rainfall were the dominant natural hazards, with Louisiana and North Carolina floods being the major loss contributors. As in 2015, hurricanes and tropical storms in 2016 continued to cause inland flooding through increased and intense rainfall—even when not making landfall, according to the report.

The National Oceanic and Atmospheric Administration (NOAA) said there were 12 individual weather and climate disaster events in the U.S. with losses exceeding $1 billion in 2016.

According to the report:

  • Based on NOAA and CoreLogic analysis, the overall flood loss in 2016, driven by six, 1,000-year plus rain events, was approximately $17 billion, which is six times greater than the overall flood damage experienced in 2015.
  • The U.S. Geological Survey (USGS) recorded 943 earthquakes of magnitude 3.0 or greater in 2016, with more than 60 percent of these earthquakes located in Oklahoma.
  • The National Interagency Fire Center (NIFC) reported a total of 5,415,121 acres burned from 62,864 separate fires in 2016. While the total acres burned in 2016 fell below the 10-year average, significant losses occurred, with thousands of homes in California and Tennessee destroyed by several smaller fires that burned in populated areas.
  • Wind activity in 2016 was slightly above average, due in large part to strong winds brought by Hurricane Matthew.
  • Hail activity in 2016 was near the average, and Texas experienced the worst of this natural hazard.
  • Tornado activity in 2016 was near average compared with previous years.
  • Hurricane Matthew developed late in the year and grew to a Category 5 storm, resulting in substantial damage along the southeastern seaboard.
  • There were below-average levels of tropical cyclone activity in the western North Pacific Basin encompassing East and Southeast Asia in 2016.

However, 2016 became known as the year without a winter. Nine winter storms impacted the U.S. in 2016, the most notable being the late-January winter storm in New York.

“History has continually shown us that it is impossible to determine exactly when or where the next wildfire, flood or earthquake will strike, which is why preparedness, response and post-loss assessment are paramount,” CoreLogic said.

Authorities Examine Hotel Owner’s Request for Help Before Italian Avalanche

avalanche barriers
As the search for survivors at an Italian hotel buried during an avalanche continues, an investigation has been launched into a distress call and emails for help by the hotel’s owner. Triggered by a series of earthquakes, the avalanche claimed the lives of at least 14 people, with 15 still missing, according to reports. A staff of eight and 20 guests were reported to have been at the hotel at the time.

Bruno Di Tommaso, owner of hotel Rigopiano, a popular ski resort, reportedly sent an email asking for help from authorities in the nearby town of Pescara. “The phones are out of service. Customers are terrified by the earthquakes and have decided to stay outdoors. We tried to do everything possible to calm them but, unable to leave because of blocked roads, they are willing to spend the night in the car,” his email read. “With our shovels we were able to clean the driveway, from the gate to the SS42 (state road). Aware of the general difficulties, we ask you to intervene.”

The UK’s Telegraph reported that prosecutors in Pescara have opened an investigation into the situation, questioning why there was no attempt to evacuate the hotel. Investigators looking into possible manslaughter charges are examining Di Tommaso’s email.

According to the Telegraph:

Authorities had reportedly promised to send a snow plow to clear the road to the hotel on Wednesday afternoon, but its arrival was constantly postponed and in the end it did not turn up at all, amid reports that some snow plow in the region were out of service while others had been dispatched to other emergencies.

There have already been claims that when the alarm was first raised, by a man who survived the avalanche by luck because he was collecting medicine from his car, his pleas for help were initially rebuffed by emergency services.

The quakes struck near Amatrice, one of the towns destroyed in August by an earthquake that left almost 300 people dead and thousands homeless.