Snow in September

Colorado went from 93o on Monday September 7 to 32o Tuesday September 8, 2020 — a change of sixty-one degrees in 24 hours. Prior to that, On September 6, Denver reached 101o making it our latest 100o day. That gave us a 48 hour change of 68o.

This weather whiplash was a result of the fact that fast-moving cold weather fronts push in behind slow-moving warm weather fronts, compressing the warm air and making it even warmer. When the cold front finally arrives, the temperature drop is dramatic. Few are as dramatic as what we saw yesterday — this was almost a record-breaker for Denver (the record being a change of 63o).

The temperature drop gave us much needed moisture, first as rain, then as snow. Although we are all glad to be out of the forest fire smoke that has plagued us for a month, it has been hard on the birds.

Before the storm hit, my husband and I made sure to fill the bird feeders. The little cheepies appreciated it this morning.

The hummingbirds, almost totally dependent on flower nectar for food, were particularly hard hit. Hummingbirds rely on their incredibly fast metabolism to keep warm. If the night is too cold, they can literally starve to death.

But we had a plan! I have a hummingbird feeder that sticks to the sliding glass door, and so is under the house eaves and would remain snow-free. The little birds completely ignore if there is any other food source available. But this morning, nothing else was clear of snow.

Female hummingbird on sliding glass door feeder. The streak across the glass is not a symptom of my poor housekeeping, but rather is an ultraviolet marker designed to keep birds from flying off our many feeders and into the windows.

The picture above was taken with natural light, because I didn’t want to startle the starving bird and scare it off it’s energy sources. But for some reason, my camera used the flash for the picture below.

The resulting photo shows off the bird’s iridescent feathers. Bird feathers create color not with pigment, but with prisms in the feathers themselves, and so change depending on the angle of the light.http://Hummer colors

Windy Days

We’ve had some windy days lately. Two days ago (October 20, 2019) we had gusts up to 40 mph (miles per hour) — it was hard to walk in that wind!

As we battled the blustery weather while walking the dogs, I happened to look to the west, where I saw lens-shaped clouds hovering over the tops of the mountains.

Once inside, I decided to clean up some photos on the computer. I happened across this shot of Longs Peak from near Estes Park from fifteen years ago.

North Face of Longs Peak

North Face of Longs Peak, October 2006

What caught my eye initially was the odd shaped cloud over the east face of the mountain top — just like what I’d seen while walking the dogs. This is called a ‘lenticular cloud’, meaning lens-shaped. Lenticular clouds indicate that the wind is really ripping, pulling relatively moister air up to the top of the mountain, where it forms a cloud as it crosses over. Although these clouds seem to stand still, in reality, they are constantly forming on the near side, then evaporating on the far.

Estes Longs 6..JPG

Notice the snow blowing off the ridge to the right (west) and dropping into the basin below the summit. This extra snow helps build glaciers.

According to the Rocky Mountain National Park Service Wind page, in the winter, the average daily wind speeds on Longs Peak are 65 mph, so the average is higher than our peak wind speed on Sunday. It often blows at over 100 mph, and the maximum wind speed recorded was in excess of 200 mph!

Suddenly, I’m more appreciative of our relatively calm air.

Bald Eagles in Wild Storm

With Winter Storm Ulmer crashing in, the bald eagles at their Fort St. Vrain nest (https://amylaw.blog/2019/02/10/eagle-cam/)have had a hard day today.

It started off with driving sleet that soaked our birds.

Both of them huddled together for about half an our — the longest I’ve seen both birds in the nest during the day.

But by 10:00 am, they were soaked.

1:03 pm Then the snow began to build up.

1:32 pm What the still photos don’t really show is how much the wind was howling, and the nest platform shaking. Denver International Airport, ten miles away from the nest, recorded 80 mile an hour gusts — hurricane force winds!

1:49 pm We kept losing power and internet, so I would go for a time without seeing the bird on the nest. When internet came back up, she’d still be there, patiently keeping her eggs warm and dry with her body.

2:11 pm She’d shake her head once in a while, but mostly she did her job — she sat on her eggs, and let the snow pile up.

4:31 pm Both eagles were back on the nest.

To all those who had to be out in this miserable storm — to keep the power on, to keep the internet up, to keep us safe, and to keep eggs warm — thank you.

This Winter’s Weather Patterns

I’ve been obsessing for the last couple of posts about how dry we’ve been this winter. This image from the NOAA GOES satellite says it all: Screenshot-2018-3-4 Western U S Infrared, Enhancement 4 - NOAA GOES Geostationary Satellite Server.png

The blue is storm clouds — Winter Storm Quinn, to be exact, that dumped feet of snow on the Sierra Nevada. It hit the Colorado border and turned north to hammer Wyoming and Montana. Now it is making another U-turn and started into the Dakotas, Nebraska and Kansas. These states are under a winter storm warning. Quinn will make its way to the storm weary east coast later this week.

What do we get? Nothing. Nada. Zip.

And this is the storm pattern we’ve had all winter.

Snowpack Levels Low

Many people don’t realize that the western part of the United States is generally arid to semi-arid. The Pacific Northwest gets biblical amounts of rain, of course, because of the coastal mountain ranges wring the water out of the wet air. Every range of mountains east of the coast catches the ever drier air, and squeezes a bit more moisture out of it. In summer, this water usually falls as rain.

But in winter, the moisture falls in the mountains as snow. The snow builds up over the course of the winter into a thick covering called snowpack. The snowpack only begins to melt in the spring. Depending on how deep the snowpack is, it often lasts into mid summer, giving regional cities and farms a long lasting reservoir of water.

The most important river in the Southwest is the Colorado River, fed by the Green, Upper Colorado, Gunnison, Uncompahgre and San Juan basins. The entire Southwest, including Arizona, Los Angeles, San Diego and the Central Valley of California depend on the rain and snow that fall in these basins that feed the Colorado.

So about this time of year, I begin to watch the snow pack in the mountains to see how dry our summer is going to be. Red is below average, green is above average, white is average, and grey is non-reporting either because it doesn’t have snowpack or there was a glitch.2018-2-23 NRCS Map Jan 2018.jpg

In January, it was looking pretty grim. (January Snowpack) Only the Northern Rockies were in good shape. That didn’t actually surprise me, because we in Colorado hadn’t had any real snow falls in November, December or January.

But starting in February, we’ve had a bunch of little storms. Most of them have dropped less than 3 inches of snow, but it has begun to build up. (February Snowpack) The snowpack isn’t deep enough to make anybody breath easy yet. But the storms have added enough to give us hope that we won’t have water restrictions this summer.

2018-2-23 NRCS Map 4 2018 Feb

NRCS National Water and Climate Center

It all depends on the next three months. Spring is our wettest season, by far. If mother nature is kind, we can make up the deficit.

Fingers crossed.

 

Night-glowing Clouds

I saw these clouds outside my back door last night, just as the sun was setting.

Evening Glories 2.jpg

 

I think they are noctilucent clouds — nocti means nigh and lucent means glowing or shining.

Noctilucent clouds form when there is a lot of ice particles from water vapor extremely high in the atmosphere.Mysterious Glowing Clouds Appear Across America’s Night Skys In fact, noctilucent clouds are the highest kind of clouds that form.

 

Photo courtesy NASA http://spaceflight.nasa.gov/gallery/images/station/crew-17/html/iss017e011632.html. The noctiluscent clouds glow right at the edge of the atmosphere.

 

If you are thinking that you’ve never seen clouds like this before, you are not alone — noctiluscent clouds have only been reported since 1883. They are, however, becoming more common and brighter. They are also showing up in the mid-latitudes — as far south as Colorado. Nobody knows why.NASA: Strange Clouds

What makes this shot so interesting is that the sun is so low on the horizon and the ice crystals that form the clouds so high that other clouds block the sun’s rays, giving the noctilucent clouds a streaked appearance.

Beautiful, mesmerizing, educational.

My mom sent me this website a couple of weeks ago. http://hint.fm/wind/index.html  It shows the direction and speed of surface winds for the entire country. This screen shot doesn’t do it justice, because on the webpage, the wind lines flow. Beautiful.Image

In addition to being mesmerizing and beautiful, the map is very educational. When you look at it closely, you’ll see that the winds are flowing from blank areas to areas where they curl and swirl. The blank areas are areas of high air pressure, pushing extra air out; the swirls are areas of low pressure, where the air is sucked in.Image

Even more interesting is that the swirling lows often represent bad weather with high winds. The lows pull in moisture, in this case from the Gulf of Mexico. This is the moisture coming in for our storm tonight.

The Wind Map was created, not by the National Weather Service, or similar group, but as an art project from Point B. Studio. http://memory.org/point.b/windmap.html

Colorado Monsoons

The weatherman is calling for thunderstorms tonight, as “monsoon moisture returns to the state.”
I always feel weather forecasters are a little presumptuous calling summer moisture in Colorado monsoons.  I mean, although we can have the occasionalImage gully-washer, our piddly precip is nothing compared with the six months of torrential rain that most people normally think of when they hear the word monsoon.
But according to weather people, “a monsoon is a wind that changes direction with the seasons”. By that definition, the Southwest, with Colorado on it’s northern edge, has a monsoon.  Summer heat on the desert of Southwest Arizona, California, old and New Mexico warms the air there, causing it to rise.  This creates a vacuum, called a low Imagepressure cell.  The low pressure sucks moist air from the Pacific and Gulfs of California and Mexico, bringing storms to the west and southwest part of the state and

You can see the center of the low pressure system as a lack of clouds in Chihuahua Mexico. This system spun up into the Front Range of Colorado, where it dropped over half an inch of rain.

You can see the center of the low pressure system as a lack of clouds in Chihuahua Mexico. This system spun up into the Front Range of Colorado, where it dropped over half an inch of rain.

occasionally onto the plains. In winter, the Southwest deserts cool, and create a high pressure cell that can keep moisture out.
These summer storms don’t compare to the classic monsoons of Asia and east Africa, but Coloradoans are usually glad to get moisture in any form.