Pacific Northwesterners feel pressured to drive to work on snow days — and think they’re good at doing so, poll finds
Weather More snow could be on the way, but here’s what’s expected the rest of the week 
Winds are expected to pick up overnight into Wednesday in the Seattle area, with gusts up to 30 mph, and much stronger winds are likely in the Cascade foothills. The wind will bring increased risk of tree damage, power outages and blowing snow.
Earthquake forecast for Puerto Rico: Dozens more large aftershocks are likely
Multiple strong and damaging earthquakes in southern Puerto Rico starting around Dec. 28, 2019 have killed at least one person, caused many serious injuries and collapsed numerous buildings, including a multistory school in the town of Guánica that luckily was empty at the time. These quakes are the most damaging to strike Puerto Rico since 1918, and the island has been under a state of emergency since Jan. 6, 2020.
This flurry of quakes includes onshore and offshore events near the town of Indios and along Puerto Rico’s southwestern coast. So far it has included 11 foreshocks – smaller earthquakes that preceded the largest event, or mainshock – with magnitudes of 4 and greater. Major quakes occurred on Jan. 6 (magnitude 5.8) and Jan. 7 (magnitude 6.4 mainshock), followed by numerous large aftershocks.
Seismologists like me are constantly working to better understand earthquakes, including advancing ways to help vulnerable communities before, during and after damaging events. The physics of earthquakes are astoundingly complex, but our abilities to forecast future earthquakes during a strong sequence of events in real time is improving.
Forecasting earthquakes is not a strict prediction – it’s more like a weather forecast, in which scientists estimate the likelihood of future earthquake activity based on quakes that have already occurred, using established statistical laws that govern earthquake behavior.
An undersea fault zone
Puerto Rico spans a complex boundary between the Caribbean and North American tectonic plates, which are sliding past each other in this region at a relative speed of about 2 centimeters per year. Over geologic time, this motion has created the Muertos Trough, a 15,000-foot depression in the sea floor south of the island.
This plate boundary is riddled with interconnected fault structures. The present activity is occurring on and near at least three interrelated large faults.
Faults are pre-existing weak zones between stronger rocks. In response to surprisingly small force (stress) changes, they rapidly slip to produce earthquakes. The “hair-trigger” nature of fault slip means that predicting the precise timing, location, and size of individual quakes is extremely challenging, if not impossible.
During an earthquake sequence, changing stresses act on nearby fault systems as stress is gradually redistributed within the Earth. This process generates thousands of protracted aftershocks.
Many earthquake sequences simply start with the mainshock. But it is not especially rare for scientists to recognize after the fact that foreshocks were occurring before the main event. Improvements in earthquake instrumentation and analysis are helping scientists detect foreshocks more often, although we have not yet figured out how to recognize them in real time.
Will one shock lead to another?
Researchers have known for over a century that the rate of earthquakes following a mainshock declines in a way that we can characterize statistically. There is also a well-established relationship between the magnitude of earthquakes and their relative number during an earthquake sequence. In most seismically active regions, for a decrease of one magnitude unit – say, from 4.0 to 3.0 – people can expect to experience about 10 times as 3s compared to 4s in a given time period.
Using such statistical relationships allows us to forecast the probability and sizes of future earthquakes while an earthquake sequence is underway. Put another way, if we are experiencing an aftershock sequence, we can project the future rate of earthquakes and what magnitudes we expect those quakes to have.
For example, as of Jan. 14, the U.S. Geological Survey forecast estimated a 3% chance of one or more aftershocks larger than magnitude 6.4 in Puerto Rico over the next seven days. It also noted that the region should expect between 40 and 210 smaller quakes, with magnitude 3 or larger – sizes that are likely to be felt – during that time.
With extended statistical modeling of earthquake sequences that include foreshock and aftershock probabilities, seismologists can forecast the likelihood of key earthquake scenarios to inform public safety efforts while earthquakes are occurring. For example, the USGS also estimated as of Jan. 13 that there was an 81% chance that the largest shock had already occurred – namely, the magnitude 6.4 quake on Jan. 7. The agency calculated a 17% chance that a closely sized “doublet” 6.4 earthquake could yet occur.
Recognizing in real time when a set of earthquakes is likely to be a foreshock sequence is a challenging and active area of earthquake forecasting research. Progress in the effective forecasting and communication of ongoing earthquake hazards could mean the difference between life and death for people in the eastern Caribbean and other seismically active areas on an increasingly urbanized planet.
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This article is republished from The Conversation, a nonprofit news site dedicated to sharing ideas from academic experts.
More than 130 dead as severe weather hits Pakistan, Afghanistan
A woman walks down a path in Quetta, Pakistan, after heavy snow
Islamabad (AFP) – Avalanches, flooding and harsh winter weather has killed more than 130 people across Pakistan and Afghanistan in recent days, officials said Tuesday, as authorities struggled to reach people stranded by heavy snowfall.
At least 93 people died and 76 were injured across Pakistan — with several still missing — while a further 39 were killed in Afghanistan, according to officials in both countries.
Forecasts suggest more harsh weather is on the way.
Pakistani Kashmir was the worst-hit area, with 62 people killed and 10 others missing, the State Disaster Management Authority said in a statement.
In the picturesque but conflict-riven Neelum Valley in Kashmir, heavy snowfall triggered several avalanches, including one that killed at least 19 people.
„An avalanche hit their village, 10 people are still missing,” the SDMA said.
Frequent avalanches and landslides occur in Kashmir during the winter, often blocking roads and leaving communities isolated.
Authorities have shuttered schools, while several highways and roads were closed across the country’s northern mountainous areas, according to officials.
„The severe snowfalls and landslides in AJK have caused misery & deaths,” tweeted Pakistan Prime Minister Imran Khan, referring to the part of Kashmir controlled by Islamabad.
To the southeast, in Balochistan province, at least 31 people had been killed in separate weather-related incidents.
„Most of those who died were women and children,” said Mohammad Younus, an official with the provincial disaster management authority, adding that hundreds remained stranded.
Across the border in Afghanistan, more than 300 houses were either destroyed or partially damaged throughout the country, said Ahmad Tamim Azimi a spokesman for the Natural Disaster Management Authority.
„A cold snap, heavy snowfall and rains that started two weeks ago have caused damage,” he said, adding that most casualties were caused after roofs collapsed under thick snow.
Hardest hit were southern Kandahar, Helmand, Zabul and western Herat provinces.
In Herat, seven people — all members of the same family and including children — died when their roof caved in, Azimi added.
Harsh winters often take a heavy toll in mountainous Afghanistan, and the country remains poor despite billions of dollars in aid from the international community.
Latest Study of 120 Million Forecasts Proves AccuWeather Forecasts Are Most Accurate
Study after study show AccuWeather forecasts are the most accurate, reliable for the protection of life and property among top weather providers.
STATE COLLEGE, Pa., Jan. 14, 2020 /PRNewswire/ — In the latest and most comprehensive statistical analysis of forecast accuracy ever undertaken, independent forecast tracker ForecastWatch reconfirmed the Superior Accuracy of AccuWeather forecasts by a significant margin over the next five sources of weather forecasts in all categories examined. The study analyzed 120 million forecasts from over 1,000 locations globally over a four-year period ending December 31, 2018, and AccuWeather was found to be the clear winner as the most public provider of forecasts in temperature, precipitation and wind speed forecast accuracy – a clean sweep of all categories — for a 1-5 days-out forecast period.
Read the full ForecastWatch four-year report here.
This comprehensive test analyzed data collected regarding weather forecasts in 1,108 locations around the world. For both 24-hour high- and low-temperature forecasts, AccuWeather was the most accurate provider with the lowest average of absolute error and the greater percentage of forecast accuracy within 3 degrees of actual temperature observations.
The study, which covered the period of January 1, 2015 through December 31, 2018, also examined precipitation forecasts and AccuWeather’s accuracy was found to be „noticeably higher than the next four providers and significantly higher than Dark Sky,” according to the report. „AccuWeather stood out as the most accurate wind speed forecaster during the 48-month period of analysis” with the lowest average absolute error, performing 28 percent better than the next closest provider. Other providers included in the report in addition to AccuWeather and Dark Sky were The Weather Channel, Weather Underground, both owned by IBM, Foreca and Intellicast.
„We are proud to provide the most accurate and actionable forecasts available for our users and clients to help them make the best decisions, protect their families, reduce losses, and increase profitability, when weather is a factor,” said Marshall Moss, AccuWeather Vice President of Forecasting and Graphics Operations. „People as well as businesses and government agencies globally depend on AccuWeather forecasts, and this latest study from ForecastWatch proves their trust in the AccuWeather forecast is well-founded.”
The independent analysis by ForecastWatch, the world’s premier weather forecast monitoring and assessment service, provides additional clear, concrete evidence that AccuWeather’s forecasts are superior to all other sources and, as a result, bring the most significant benefits to people and businesses.
„The disruptive impact of weather on lives and businesses is significant,” said Dr. Joel N. Myers, AccuWeather Founder and CEO. „We are extremely proud of our track record of forecast accuracy, but the margin of exceptional value we provide goes well beyond what is demonstrated in this latest independent report. Our weather forecasts are more localized than other sources, more detailed, and extend further into the future.”
„The powerful combination of accuracy and detail, both in location and time, and AccuWeather’s emphasis on how predicted weather conditions will impact its users and business clients, make AccuWeather’s forecasts many times more valuable than our statistical advantages proven in this latest study,” he continued.
