How the Santa Ana Winds Help Wildfires Spread

The Santa Ana winds are notorious for exacerbating wildfires in southern California.

These strong winds blow warm, dry air across the region at different times of the year, but mainly occur in the late autumn. They form when a large pressure difference builds up between the Great Basin – a desert that covers most of Nevada and parts of Utah – and the coastal region around LA. This pressure gradient funnels air downhill and through the passes of the San Gabriel and San Bernardino mountains toward the Pacific. According to the NWS, the Santa Ana winds can easily exceed 40 mph.

Originating in the high desert, the air starts off cool and dry. But as it travels downslope, the air compresses and warms. In fact, it warms about 5°F for every 1000 feet it descends. This dries out the region’s vegetation, leaving it susceptible to any type of spark. The fast-moving winds then fan the flames of any wildfires that ignite.

The Santa Ana winds are named for Santa Ana Canyon in Orange County, CA.

Credit: NWS

Energy Flow: A Wind Powered Public Art Installation in Pittsburgh

On a recent visit to Pittsburgh, PA I had the opportunity to see “Energy Flow”, a wind-powered art installation on Rachel Carson Bridge. It was created in 2016 through a collaboration between environmental artist, Andrea Polli, and WindStax, a Pittsburgh-based wind turbine manufacturer.

Using sixteen small vertical axis wind turbines to power 27,000 LED lights, the piece produces a rainbow of colors up and down the bridge’s vertical supports. The light show visualizes the local wind speed and direction in real time as detected by an onsite weather station. The project also has battery storage to power the lights for up to twelve hours when the wind is not blowing. In essence, this artwork turned the bridge into a micro-grid – a single location where power is produced, stored and consumed.

As a site-specific art installation, it honors the environmental legacy of Rachel Carson (1907-1964). She was a native of the Pittsburgh area who went on to become a marine biologist and famous environmental writer. Her books, such as “Silent Spring”, are widely credited with inspiring the environmental movement of the 1960s that eventually brought about federal laws like the Clean Air Act.

The project also highlights Pittsburgh’s new focus on technological innovation and sustainability. Once known as the “Smokey City”, because of all the pollution that billowed from its plethora of mills and factories, Pittsburgh has refocused its economy and remade its image. Situated at the confluence of three rivers – the Allegheny, Monongahela, and Ohio – it is home to an astounding 446 bridges and is now often referred to as the “City of Bridges”. The Rachel Carson Bridge was originally, and rather simply, called the Ninth Street Bridge after it opened in 1926. It was renamed on Earth Day 2006.

“Energy Flow” was only expected to be up for a few months to celebrate Pittsburgh’s Bicentennial. But due to popular demand, its run has been extended through the end of 2018.

“Energy Flow” Wind/Light Installation on Rachel Carson Bridge, Pittsburgh, PA. Credit: Covestro LLC

Weather and the NYC Macy’s Thanksgiving Day Parade

The Macy’s Thanksgiving Day Parade is a long-standing holiday tradition in New York City.  For 91 years, it has marched rain or shine. Nevertheless, the weather has been a factor in the event several times over the years.

Famous for its giant character balloons, high winds are the main weather challenge for the parade. According to city guidelines, the multi-story balloons cannot fly if there are sustained winds in excess of 23 mph or gusts higher than 34 mph. These regulations were put in place following a 1997 incident where gusty winds sent the “Cat in the Hat” balloon careening into a light post, which caused debris to fall on spectators.

The only time the balloons were grounded for the entire parade was in 1971 when torrential rain swept across the city. In 1989, a snowstorm brought the Big Apple a white Thanksgiving with 4.7 inches of snow measured in Central Park. The parade marched on that year but without the “Snoopy” and “Bugs Bunny” balloons as they were damaged by high winds earlier that morning.

This year, the wind is not expected to be a problem. Temperatures, however, are forecast to be a bit chilly – mostly in the 30s during the parade hours. So, bundle up if you are planning to be outside along the route.

Marching from West 77th Street to West 34th Street in Manhattan, the 91st Annual Macy’s Thanksgiving Day Parade is scheduled to begin at 9 AM on Thursday morning.

Happy Thanksgiving!

Paddington Bear Balloon floats down 6th Ave in Macy’s Thanksgiving Day Parade. Credit: Macy’s

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

Hot Temperatures and Strong Winds Fuel Western Wildfires

Summer is wildfire season in the American West and this year it is off to an explosive start.

As of Wednesday, according to the National Interagency Fire Center, thirty large wildfires – defined as greater than 100 acres – are burning in ten western states.  These include Alaska, Arizona, California, Idaho, New Mexico, Nevada, Oregon, Texas, Utah, and Washington.

The largest is the Brian Head Fire in southern Utah. It has burned approximately 50,000 acres and forced the evacuation of nearly 1500 people. Ignited on June 17, the massive blaze is only 10% contained.

Another hard hit state is Arizona, where six large fires are currently burning. The governor, Doug Ducey, has declared a state of emergency in Yavapai County in response to the Goodwin Fire, which has burned more than 20,000 acres near the Prescott National Forest. Local officials have ordered the full evacuation of the town of Mayer, AZ.

These huge fires are being fueled by extremely hot and dry conditions that have left the region’s vegetation susceptible to any type of spark. Just a few days ago, excessive heat advisories were in effect for a large swath of the area as temperatures soared into the triple digits. Now, high winds are fanning the flames and helping the fires to spread.

Year to date, 2.7 million acres in the US have been charred. The country’s worst wildfire season on record was 2015 when more than ten million acres burned.

Brian Head Fire, UT. Credit: Desert News

Weather Lingo: Rain Shadow

The world of weather has some interesting words and phrases. One of these is “Rain Shadow”.

While it sounds rather poetic, a rain shadow refers to the land area on the leeside of a mountain that is exceptionally dry. Mountains act as barriers for weather systems traveling in a region’s prevailing winds, forcing them to drop most of their moisture on the windward side before they can pass.

As an air mass rises up and over a mountain, it enters an area of lower atmospheric pressure where it expands and cools. As a result, the moisture it contains condenses, clouds form, and precipitation falls. After the air mass moves over the mountain, it starts to descend the other side. The air is warmed by compression and the clouds dissipate. This means little to no rain falls on the leeward side.

Rain shadows are found all over the world, from the Tibetan Plateau in Asia to the Atacama Desert in South America. Here in the US, Death Valley is a famous example as it lies in the rain shadow of four different mountain ranges.

The Rain Shadow Effect. Credit: Kagee Commons

If You Don’t Like the Weather in Iceland, Just Wait Five Minutes

In Iceland, people are fond of saying, “If you don’t like the weather, just wait five minutes.” This popular expression is written on everything from t-shirts to coasters, and during the course of my recent visit I also found it to be true.

The notoriously changeable weather of this island nation is largely the result of its location. Situated just south of the Arctic Circle, Iceland sits at the border between the Arctic Ocean with cold air masses to the north and the Atlantic Ocean with milder air masses to the south. A branch of the warm Gulf Stream Current known as the Irminger Current also flows along the country’s southern and western shores moderating the climate. As this mild air interacts with cold arctic air, it produces frequent changes in the weather. A relatively mild, sunny day can quickly turn cold and rainy. Strong winds are also very common.

So, when in Iceland, heed the advice of the locals and be prepared for all four seasons on any given day.

Coaster for sale with the popular saying, " Welcome to Iceland. If you don't like the weather, just wait five minutes." Credit/Source: Gullfoss.is

Coaster for sale with the popular saying, “Welcome to Iceland. If you don’t like the weather, just wait five minutes.” Credit/Source: Gullfoss.is

A March-like Chill in May for NYC

The calendar says mid-May, but it felt more like March in New York City this weekend.

After a warm spring day on Saturday with readings in the 70s, a cold front swept through the region ushering in significantly cooler conditions. The high on Sunday only reached 57°F, which is 13°F below average. This dramatic cool down was also accompanied by strong winds with gusts in excess of 40-mph.

Moving from Sunday into Monday, the over-night low in Central Park fell to a chilly 43°F. That is the coolest May temperature the city has seen in three years. It was also just one degree shy of tying the record low of 42°F set in 1878. Our normal low temperature for this time of year is 54°F.

With Memorial Day – the un-official start of summer – just two weeks away, many New Yorkers will be happy to hear that temperatures are expected to rebound to more seasonable levels later this week.

High Winds Whip through NYC

March, a month where the seasons transition from winter to spring, can produce some fickle weather. But, it is probably most famous for strong winds, and they were on full display in New York City yesterday.

According to the NWS, sustained winds of 25mph were measured in Central Park and gusts reached as high as 45mph. A wind advisory was issued in the afternoon and remains in effect until later this evening.

Below is a short video of strong winds whipping a tree in a NYC backyard.  Even though it is largely protected by buildings, it still moves quite a bit.

Video Credit: The Weather Gamut.

Microburst Winds Damage Town in Massachusetts

A strong microburst toppled trees and power-lines in the town of Easthampton, Massachusetts early Wednesday morning. With winds in excess of 100mph, the damage to the area was equivalent to an EF-1 tornado.

According to the National Weather Service in Boston, the powerful storm cut a path of destruction one mile long and a quarter mile wide. No serious injuries have been reported.

A microburst is a powerful, but short-lived, downward moving column of air generated by a thunderstorm. It produces intense straight-line winds – as opposed to the rotating winds of a tornado – that generally impact localized areas less than 2.5 miles wide.

microburst

How a mircoburst works.   Credit: NOAA

Damage from microburst in Easthampton, MA.  Credit: MassLive

Damage from microburst in Easthampton, MA.   Credit: MassLive