La Niña is Back and Likely to Stick Around Through the Winter

La Niña, the cooler counterpart of El Niño, has returned for the second year in a row.

It is a natural event associated with the larger El Niño-Southern Oscillation (ENSO) climate pattern and is marked by cooler-than-average ocean water in the central and eastern tropical Pacific. More specifically, a La Niña event is declared when sea surface temperatures in that region are at least 0.5°C below average and accompanied by a consistent atmospheric response. This includes more clouds and rain over the western Pacific and less over the central part of that basin. Stronger than average upper-level wind is also a key atmospheric indicator.

The relatively cool water associated with La Niña creates an area of high pressure over the Pacific and pushes the jet stream northward. This, in turn, affects weather patterns around the globe.

In the US, a La Niña event typically brings the southern states conditions that are warmer and drier than normal. The northern tier, on the other hand, usually experiences below average temperatures with the northwest and Great Lakes regions receiving above average precipitation.

That said, every La Niña event is different. There are also other atmospheric factors, such as blocking patterns, which can influence the weather.

According to NOAA, there is a 65%-75% chance of weak La Niña conditions continuing through the winter months.

Typical Winter La Niña jet stream pattern over North America. Credit: NOAA/Climate Prediction Center.

Massive Federal Science Report Says Humans Cause Climate Change

The Fourth US National Climate Assessment (NCA4) was released on Friday. It clearly states that climate change is real, it is happening now, and human activities are the main cause.

The first volume of the assessment – the Climate Science Special Report – says the average global temperature has increased 1.8°F (1°C) during the past 115 years (1901-2016). “This period is now the warmest in the history of modern civilization,” according to the report. It also says that “it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century.” Going even further, the report concludes, “there is no convincing alternative explanation supported by the extent of the observational evidence.”

With a focus on the US, the report says the average annual temperature in the contiguous forty-eight states has increased by 1.2°F (0.7°C) since 1986, relative to the previous century. It is projected to increase 2.5°F (1.4°C) by 2050.

In addition to warming, other aspects of climate change are highlighted in the massive report. One of these is sea level rise. Since 1900, the average global sea level has gone up 8 inches. Of that total, a 3-inch rise has occurred since 1993. This rate of rising, according to the report, “is greater than during any preceding century in at least 2,800 years.”

Moving forward, all projections show sea level continuing to rise. An increase of several inches is likely in the next fifteen years and 1 to 4 feet is estimated by 2100. A rise of as much as 8 feet by the end of the century, however, “cannot be ruled out”, the report warns. This is especially true if the ice sheets in Greenland and Antarctica prove to be more sensitive to rising temperatures than expected. In cities along the Gulf Coast and Eastern Seaboard, where daily tidal flooding is already a problem, sea level rise is forecast to be even higher than the global average.

The report also contains details on how extreme weather is changing across the US. For example, heavy rainfall events are ”increasing in intensity and duration” nationwide with the biggest increases happening in the northeast. In the west, the incidence of large forest fires has been rising since 1980 and is expected to increase even further in the coming years. Heat waves, unsurprisingly, have also become more frequent while cold waves have become less frequent.

Looking beyond the next few decades, the NCA says the magnitude of climate change depends on the amount of greenhouse gases that are added to the atmosphere. The level of carbon dioxide in the air today has already passed 400 parts per million, a number not seen in 3 million years. If emissions are not reined in, the average global temperature could increase by as much as 9°F (5°C) by the end of this century. According to the report, “the further and the faster the Earth system is pushed towards warming, the greater the risk of unanticipated changes and impacts.”

Mandated by Congress under the Global Change Research Act of 1990, this exhaustive climate report was produced by hundreds of experts from government agencies as well as academia and was peer-reviewed by the National Academy of Sciences. Published every four years, it is considered this country’s most authoritative statement on climate change.

Its findings, however, are in stark contrast to the words and actions of the Trump Administration. The President has called climate change a “hoax” and in June announced that he is withdrawing the US from the Paris Climate Agreement – an international accord that aims to reduce greenhouse gases and limit global warming to 2°C (3.6°F). The US and Syria are now the only two countries not part of the historic agreement.

Global annual average temperature (left) and surface temperature change for the period 1986–2016 relative to 1901–1960. Credit: NCA4

Road Trip Highlights US Environmental History and Shows Big Changes are Possible

Last week, I was in Pittsburgh, PA to serve as a Mentor at a Climate Reality Project training event. Having never been in that part of the country before, I spent a few extra days to explore the area. The overall experience felt like a road trip through US environmental history and was a great reminder that large-scale changes are possible, especially in this era of climate policy backpedaling.

First stop: Donora, PA. This Pittsburgh suburb was the site of the “Killer Smog of 1948”. As the longtime home of the Donora Zinc Works Factory and the American Steel and Wire Plant, smoke-filled skies were not unusual here in the early part of the 20th century. In October 1948, however, the air turned deadly. An inversion layer, a weather phenomenon where the temperature in the atmosphere increases with height instead of decreasing, trapped emissions from the factories. The sulfuric acid, nitrogen dioxide, fluorine, and other poisonous gases created a thick, yellowish smog. It hung over the area until the weather pattern changed five days later. As a result, twenty-six people died and thousands of others became ill.

This tragedy garnered national attention and spurred federal regulations on air pollution. In 1955, Congress provided funding for pollution research and later passed the Clean Air Act of 1963. In 1970, the EPA was created and Congress passed the Clean Air Act Amendments, which established national air quality standards.

Donora is proud of their role in this change in national environmental policy. Outside of their local Historical Society/Smog Museum is a sign that says “Clean Air Started Here”.

Another highlight of this trip was Cuyahoga Valley National Park in northeastern Ohio. Established as a National Recreation Area in 1974 and upgraded to a National Park in 2000, it reclaimed and now preserves the natural landscape along twenty-two miles of the Cuyahoga River between Akron and Cleveland, OH. While relatively small, the river is an icon of American environmental history.

Starting in the late 1800s, the river became highly industrialized. For more than a century, the steel mills and factories that lined its banks dumped untreated waste directly into the river. The Cuyahoga became so polluted that it caught on fire thirteen times.

The last time was June 22, 1969, when sparks from a passing train ignited the oil and debris floating in the water. This fire, while not the largest or deadliest in the river’s history, caught the attention of Time Magazine and became national news. Appearing in their August 1 issue, the article described the Cuyahoga as a river that “oozes rather than flows”.

During the late 19th and early 20th century, river fires were common and seen as the price of industrial progress and prosperity. By the 1960’s, however, that way of thinking was starting to change. The country was becoming more environmentally aware and the Cuyahoga River fire put a national spotlight on the need to protect waterways from industrial pollution. The event helped to galvanize the Water Quality Improvement Act of 1970 and the Clean Water Act of 1972.

In the years since, the Cuyahoga River has made an amazing comeback. Bald Eagles – a symbolic emblem of this country – have returned to fish its waters and nest along its banks. In 1998, it was designated as an American Heritage River to recognize its historical significance.

Today, our environmental challenge is the carbon pollution that drives climate change. Its solution, as with conservation issues in the past, lies with policy adjustments. While these types of large changes can sometimes seem impossible, history reminds us that they are not. All that is required is the will to act. As Nelson Mandela once said, “It always seems impossible until it’s done”.

Cuyahoga River, past and present. Credit: Cleveland State University Library

Wildfire Outbreak in Northern California

Northern California is ablaze with wildfires.

As of Thursday, according to CalFire, 22 wildfires are burning in the Golden State. They have scorched over 190,000 acres and forced the evacuation of entire neighborhoods. Officials say at least 26 people have been killed and more than 400 are missing. In terms of property damage, they conservatively estimate that 3,500 homes and structures have been destroyed.

The smoke and ash from these fires are also causing widespread air quality issues. In the Bay Area, well outside of the burn zone, air quality reached historically poor levels this week.

These huge fires are largely the result of climate whiplash. California has distinct wet and dry seasons, but they have been extreme recently. After years of drought, this winter brought the state record amounts of precipitation that spurred explosive new plant growth. Then during the summer, which was the state’s warmest on record and unusually dry, all that vegetation turned to tinder.

Making matters worse, the region’s seasonal winds known as the Diablo Winds began blowing over the weekend. They reportedly reached speeds as high as 70mph in some areas. Blowing east to west, these winds warm from compression as they flow downslope from the mountains towards the coast and dry out vegetation even further. They also fan the flames of any fire already burning and can cause it to spread very quickly.

The Diablo Winds are essentially the same type of air current as the famous Santa Ana winds in southern California. They only really differ in location and name. The Diablo Winds are named for Mount Diablo in the East Bay area and the Santa Ana Winds are the namesake of Santa Ana Canyon in Orange County.

Wildfires are not unusual in California, but this outbreak is considered one of the worst in state history. The exact cause of the fires is still unknown.

Wildfire burns near Glen Ellen, CA. Credit: The SF Chronicle

Hurricane Nate Slams Gulf Coast

Hurricane Nate, the 14th named storm of the 2017 Atlantic Hurricane season, made two landfalls along the US Gulf Coast this weekend. The first was near the mouth of the Mississippi River in Louisiana and the second was near Biloxi, Mississippi.

Coming ashore with 85mph winds, this category-1 hurricane generated a significant storm surge that swamped parts of the region from Louisiana to the Florida Panhandle. One of the hardest hit areas was Pascagoula, MS where a storm surge of 6.3 feet was reported. The storm also downed trees and caused widespread power outages.

Moving inland, Nate was soon downgraded to a tropical depression. However, it still spawned a number of destructive tornados from Alabama to North Carolina. They ranged in strength from EF-0 to EF-2.

Nate was the first hurricane to make landfall in Mississippi since Katrina in 2005.

Credit: NOAA/NASA GOES

Hurricane Maria Devastates Puerto Rico

Hurricane Maria, the 13th named storm of this Atlantic Hurricane season, made landfall in Yabucoa, Puerto Rico on Wednesday morning. It was the strongest storm to hit the US Territory since 1928.

Coming ashore with sustained winds measured up to 155mph, Maria was classified as a high-end category-four hurricane. Its powerful winds sheared roofs and balconies off buildings, uprooted trees, and toppled power lines. In addition, the storm’s torrential rain unleashed devastating flooding across the island. More than 30 inches of rain was reported near Caguas, PR.

Local authorities say the entire island, home to 3.5 million people, is without power. They do not expect it to be fully restored for four to six months. This unusually lengthy timeframe is largely due to the fact that Puerto Rico is an island with rugged terrain and an electrical grid that has been crumbling for years from a lack of maintenance. The Puerto Rico Electric Power Authority, the territory’s sole provider of electricity, effectively filed for bankruptcy in July.

Before making landfall in Puerto Rico, Maria roared through the Caribbean and reached category-five strength. It battered several other islands, including the US Virgin Islands, which were still reeling from the devastation caused by Hurricane Irma less than two weeks ago. As of Thursday, the death toll from Maria stands at seventeen. But sadly, this number is expected to increase as search and rescue efforts continue across the region.

Maria was the third category-four hurricane to hit the US, or one of its territories, in less than a month. In 166 years of record keeping, this has never happened before.

Hurricane Maria moves across Puerto Rico. Credit: NOAA/NASA

Hurricane Irma Batters Entire State of Florida

Hurricane Irma, the 9th named storm of this Atlantic Hurricane season, made two landfalls in Florida on Sunday. First, its eye crossed Cudjoe Key, just east of Key West, as a category-4 hurricane. Then, a few hours later,  it came ashore at Marco Island on the state’s Gulf Coast as a category-3 storm.

Measuring about 425 miles in diameter, Irma was wider than the Florida peninsula and its effects were felt across the entire Sunshine state. Powerful winds, heavy rain, and storm surge flooding caused catastrophic property damage in the Keys and along both coasts.

In the west, Naples, FL experienced wind gusts up to 142mph – the strongest recorded during the storm. On the east coast, gusts were clocked up to 109mph in the Miami/Fort Lauderdale area, where three high-rise construction cranes collapsed in the strong winds. The storm surge in both Biscayne Bay and Naples was about four feet above normal tide levels.  In the hard hit Keys, according to FEMA, 25% of homes were completely destroyed and about 65% sustained serious damage.

Reports of toppled trees and downed power lines are widespread. The Department of Homeland Security says 15 million people lost power, making it one of the largest power outages in US history.

Moving north and shifting inland, Irma was downgraded to a tropical storm on Monday. Nevertheless, it continued to pack a powerful punch. Jacksonville, FL reported a record six-foot storm surge and the worst flooding it has seen since Hurricane Dora moved through the area in 1964.

Irma’s wrath was also felt in parts of Georgia and the Carolinas. Along the coast, storm surge flooding inundated communities from Savannah, GA to Charleston, SC. Further inland, the NWS issued its first ever tropical storm warning for the metro-Atlanta area.

Coming just sixteen days after Hurricane Harvey, Irma was the second category-4 storm to make landfall in the US this season. In 166 years of record keeping, never before have two Atlantic hurricanes of such intensity hit this country during the same year.

The death toll from this historic storm currently stands at forty-three, including five fatalities reported in Florida, three in Georgia, and one in South Carolina. The rest are from the Caribbean, where Irma hit multiple islands as a Category 5 storm late last week. Sadly, these numbers are expected to rise as search and rescue efforts continue. The entire region faces a long and expensive road to recovery ahead.

Hurricane Irma makes landfall in southern Florida as a Category-4 storm. Credit: NASA

Harvey Sets New Rainfall Record for Continental US

Battering southeast Texas for days, Tropical Storm Harvey has produced more rainfall than any other single storm on record in the contiguous United States.

According to the NWS, 51.88 inches of rain was reported at a gauge near Mont Belvieu at Cedar Bayou, about 40 miles east of Houston. This crushes the previous record of 48 inches that was set by Tropical Storm Amelia which hit Medina, TX in 1978.

The record for the entire US, however, still stands. It was set in 1950 when Hurricane Hiki dropped 52 inches of rain on Hawaii.

Source: NWS

Harvey Unleashes Catastrophic Flooding in Houston

Days after making landfall as a category-4 hurricane, Harvey, now a tropical storm, is still battering southeast Texas. Relentless rain has unleashed catastrophic flooding across the region, including Houston – this country’s fourth largest city.

While this devastating event is still unfolding, rainfall totals in some areas have already exceeded two feet. Dayton, TX, northeast of Houston, has reported a staggering 39.72 inches of rain since Thursday. Houston Intercontinental Airport (IAH) has posted 25.66 inches of rain so far and reported its wettest calendar day on record on Sunday with 16.07 inches.

This intense rainfall is causing the many rivers, creeks, and bayous in the metro Houston area to overflow their banks and flood homes, businesses, and major roadways – effectively paralyzing the area. Rainfall rates reached as high as 3 inches per hour on Sunday in some areas, prompting the NWS to issue a flash flood emergency – the highest level of a flood alert.

No evacuation order was issued ahead of the storm in Houston and residents were told to shelter in place. Now, thousands of high water rescues are taking place via boat and helicopter to save people trapped in their homes. The situation has many people comparing it to scenes that played out in the aftermath of Hurricane Katrina in New Orleans. The mayor of Houston, Sylvester Turner, has opened the massive George R. Brown Convention Center to be used as a shelter. As of Monday, eight storm-related deaths have been reported. But sadly, local authorities expect this number to increase as the water continues to rise.

Southeast Texas is no stranger to flooding. However, officials in Houston say this event is the worst they have seen since Tropical Storm Allison in 2001. That storm dumped more than 35 inches of rain on the metro area over the course of five days and caused $5 billion worth of damage.

Harvey, wedged between two areas of high pressure, is expected to linger over the region for several more days and dump an additional 15 to 25 inches of rain. Forecasters at the NWS say the rainfall total for this storm could reach an unprecedented 50 inches in some spots.

Eighteen counties in Texas, according to Governor Greg Abbot, have been declared federal disaster areas because of this storm.

TS Harvey caused unprecedented flooding in Houston, TX. Credit: Aryan Midas

Hurricane Harvey Hammers Texas

Hurricane Harvey, the eighth named storm of the 2017 Atlantic Hurricane Season, made landfall in Rockport, TX late Friday night. It was the strongest storm to hit the United States in twelve years.

Coming ashore with winds measured up to 130mph, Harvey was classified as a Category-4 hurricane on the Saffir-Simpson Scale. These powerful winds along with storm surge flooding and torrential rain caused catastrophic property damage across the Texas Coastal Bend region. It also downed trees and left hundreds of thousands of people without power. To date, according to local officials, only two storm-related deaths have been reported.

Moving inland, toward Houston, Harvey weakened to a Tropical Storm on Saturday afternoon. However, despite this downgrade in wind speed, its rain bands are still drawing moisture from the Gulf of Mexico and unleashing massive amounts of precipitation. Wedged between two areas of high pressure, the storm is essentially stalled over the region. Therefore, even more flooding rain is expected over the next several days.

Harvey was the first major hurricane – category 3 or higher – to make landfall in the Lone Star State since Hurricane Carla in September 1961.

Satellite imagery from NOAA shows Hurricane Harvey along the Texas Coast. Credit: NOAA