Meteorologist Britta Merwin

The saying goes, “April showers bring May Flowers”, but what happens after a May snowstorm?

Many folks from Wyoming, through the Colorado Rockies, into the Dakotas walked to the window on May 1st and 2nd to see a winter wonderland. Western South Dakota, including Rapid City, was actually under a blizzard warning during the storm and received over a foot of snow! It is late season storms like this that leave people not only wondering if their calendar is right but if this is normal?

To explore what really is normal we head to my favorite state of Colorado, big surprise!

The average snowfall for Denver in May is 1.3’’ and every two years out of five years snow is actually recorded in the mile high city. The past decade hardly any snowfall was recorded in the area but a few days ago the first week of May 2008 hit the books with 0.7’’ of snow in Denver. Thankfully this was nowhere near the record May snowfall of 15.5’’ in 1898.

It is hard to say what is normal when it comes to weather especially in Colorado. The month of May is know for is variety across the Front Range. Daytime highs can fall between 40 degrees one day and then a couple days later can rebound into the 70s and 80s.

The latest freeze for the area is usually on June 8th. With cooler temperatures staying in the higher elevations ski resorts can stay open late into the season by making snow overnight. This year Arapahoe Basin, known as A-Basin to the locals, is open until early June!

May is also the wettest month on average for Denver with precipitation recorded once out of every three days. And although Colorado is known for its sunshine (some say 300 days of sun a year) May is characterized as the cloudiest month tied with November.

So from fat snowflakes to beautiful summer like conditions your calendar is right, it really is May.

Posted by Keith Davis at 11:40 AM | Permalink | Comments (0)

Meteorologist Samantha Davies

The vineyards in Northern California have been hit by one of the worst frosts in nearly 30 years. Nighttime temperatures at the end of April were in the 20’s. Frost alarms on the vines were set off signaling growers of the freezing temperatures. Frost is not unusual in California, but this season it was particularly bad because of the severity and the duration of the frost. The cold temperatures lasted about twenty nights in a row.

Frost damaged Merlot grapevines are shown at a vineyard in the Stag's Leap Wine District in Napa, Calif. (AP Photo/Eric Risberg)

Growers in Napa and Mendocino are still assessing the damage; it is expected to be in the Millions. It will not be until June until the damage is fully assessed, but growers are expected to have a smaller than average harvest this year.

There are a few things that can be done to prevent frost on the vineyards. Farmers can install wind machines. This will circulate the air, letting warmer air in keeping the cold air off the vines. Irrigation is another technique that can be used. This deposits a thin layer of ice over the buds, which believe it or not, can actually keep them at 32 degrees preventing damage from below freezing temperatures.

Posted by Britta Merwin at 01:34 PM | Permalink | Comments (0)

Meteorologist Britta Merwin

Plumes of toxic gases spew from Kilauea everyday on the Big Island of Hawaii. The volcano has actually been continuously erupting since 1983. With this activity occurring everyday, an estimated 2,000 tons of vog is created each day over the Big Island. Recently the production of vog has increased due to a new vent opening on the volcano this past March. This secondary vent is now increasing the amount of sulfur dioxide spilling over the island. This increase in toxic gas is killing crops, aggravating people’s respiratory illnesses, and even prompted the evacuation of visitors from Hawaii Volcanoes National Park.

So what exactly is vog? Vog is volcanic smog. Basically sulfur dioxide and other volcanic particles are emitted into the atmosphere during an eruption. These pollutants then mix with oxygen and water vapor. A key ingredient of vog is sunlight; the intense radiation is needed to create volcanic smog.

Many people wonder is vog like smog? Although the two are very similar and cause city skylines to appear draped in a dark fog the two phenomena are different.

Smog is actually created by certain chemicals that result in the incomplete combustion of fuels and the combination of N2 and O2 in internal combustion engines.

Both require pollutants combining with water vapor, oxygen, and sunlight but vog and smog include a different set of pollutants.

Vog is harmful to plants, animals, and humans. For people with sensitive respiratory systems the presence of vog can worsen symptoms and it can actually cause asthma and lung disease. Large amounts of vog can even irritate a healthy person’s ability to breath and cause irritations of the eyes and skin.

Posted by Britta Merwin at 11:40 AM | Permalink | Comments (0)