Friday, February 12, 2021

Why Portland, OR and Seattle, WA Get Snow and Ice Storms

National Weather Service Winter Alerts Issued Thursday, February 11, 2021 for parts of Washington and Oregon. Note the Blizzard Warning for the tiny area on the map, The Columbia River Gorge.

Rough winter weather is being forecast for the Pacific Northwest. In fact, Blizzard Warnings were issued, not for the mountains, but the Columbia River Gorge only a few miles from Portland.  In Portland and Seattle Winter Storm Warnings were posted. Don't these cities normally just gets clouds and rain in winter?  Yes, for the most part they do, however under specific weather patterns, they can get their share of winter weather.  

I find mountain weather so very interesting. Combine the largest ocean in the world on one side of these Pacific Northwest cities and some of the tallest and snowiest mountains in North America to the east and you get a wonderful natural laboratory to study the weather!

Portland, Oregon and Seattle, Washington are located on the Pacific Northwest Coast in between the warm and moist Pacific Ocean to the west and the towering Cascade Mountains to the east.  Because of their proximity to the coast and their sea level elevation, both cities receive very little in the way of winter weather.  In fact, Portland receives only 4.3 inches of snow annually and Seattle gets just a bit more at 6.8 inches.

You will want to look closely at two features on the map above, The Fraser River Valley in southern British Columbia, Canada up north and the Columbia Rover Gorge in the southern part of the map.  These two geographic features play a big role in wintry weather for Seattle and Portland. 

The biggest reason these two locations do not get much snow is that it is just too warm long the coast to see much in the way of frozen precipitation. Essentially, The Cascades act as a gigantic wall to keep the cold air that comes down out of Canada to the east of the mountains, protecting the West Coast from frequent outbreaks of really cold air.  

Down along the coast, at sea-level there aren’t many ways to get cold enough for snow or ice.  Just east of the coast however, it snows “to beat the band” in the Cascades because higher elevations alone produce a much colder environment, one that is much more favorable for snow.  The temperature drops a little more than 3 degrees for every 1,000 ft. elevation. If you go up 5-10 thousand feet that's a 15 to 30 degree drop in temperature, more than enough in the winter to make snow.  The extra lift created by prevailing westerly onshore winds heading up the slopes of these 10,000+ ft. mountains also wrings out more precipitation from the moisture-laden air. 

It’s crazy when you realize that Seattle is only about 50 miles as the crow flies from Mt Rainier. The mountain tops out at 14,411 ft. and at the Paradise Ranger Station, elevation 5400 ft., they average 639 inches of snow each winter. Back in the winter of 1971-72 they picked up 1,122 inches of snow, a world record at that time, while Seattle averages 6.8" of snow.

Wow!! What a difference 50 miles makes. This may be one of the greatest differences in annual snowfall over such a small distance. 

So, what does it take to get snowfall in locations like Seattle and Portland, its neighbor to the south? Well, you need a way to get cold air across the Cascades and into those coastal areas. A few times each winter season, the large-scale weather pattern sets up to provide a way to get that dense, cold air across the mountains.  Those conditions begin with the presence of an Arctic High Pressure system over western Canada that pushes very cold air down along the east side of the western mountain ranges.


In Seattle and locales around the Olympic Peninsula, that cold air can come through gaps in the mountains that are to the east.  Under conditions with strong High Pressure east of the Cascades and Low Pressure just off the Pacific coast, a pressure gradient develops from east to west. The wind wants to blow from high to low pressure, like letting air out of a balloon. The really cold and dense air from east of the Cascades wants to get west, but it’s so dense it is tough to get over the mountains.  However, where there are gaps in the mountains, it offers a perfect gateway for the air to move through, sometimes all the way to the coast.  

The Fraser River Valley, just across the Canadian border in British Columbia serves as a significant gateway for that arctic air to pass through and it is often responsible for pre-conditioning the temperature of the lower atmosphere with cold air to produce snowfall.


Portland has some of the same characteristics as Seattle, but is located about 100 miles south.  Instead of getting cold air through the Fraser River Outflow, Portland is right at the mouth of the Columbia River, which runs from east to west through the Cascades and down to the coast. 

The gorge is the only near sea level gap through the Cascades. Its average width is about 3 miles at river level.  It stretches 120 miles back to the east and the western entrance is less than 15 miles from Portland.  The crest of the Cascades lies about 45 mi east of Portland.  

One of the most beautiful places in the world in my book, The Columbia River Gorge features some amazing weather, including strong winds that allow for some great wind surfing. In winter, maybe not as inviting.


In fact, Portland Oregon gets a majority of its wintry weather when the winds are out of an easterly direction. On a broad sense of course, you would be hard pressed to get snow or ice from the westerly winds coming off that warm ocean.  However, similar to Washington State, a large pressure gradient between arctic air and strong High Pressure to the east of the Cascades and Low pressure off the Pacific Coast results in a flow of cold, dense air from east to west through the gorge.  

The graph below shows, without a doubt, the dependence on wind direction to produce wintry precipitation in Portland.  When the low-level winds are from the east and the mid-level flow is from the west, it becomes the “perfect storm” of sorts for snow or ice.  Snow will occur under conditions when the atmosphere is also cold aloft.  Typically, that comes with closed upper levels “cold-core” Lows.  However, if the air aloft is warm and the easterly gap winds are below freezing, then precipitation formed way up in the clouds in the form of snow melts as it drops through the warmer mid-levels then refreezes as it hits the surface where the temperatures are below the freezing mark. 

The distribution of annual snowfall and freezing rain vs. wind direction clearly shows just how important the role of easterly winds is for wintry weather in Portland, Oregon. 

The soundings below, taken at Salem Oregon, show the difference in the temperature throughout the atmosphere for snow vs. ice events in the Lowlands in Oregon to the west of the mountains including Portland. Notice the above-freezing layer in the sounding on the left, perfect for melting snow which then freezes on contact where surface temperatures are well below freezing. The sounding on the right shows above freezing surface temperatures but the atmosphere quickly cools below freezing a few hundred feet off the ground. That temperature and moisture profile results in heavy, wet snow. 

No, they don’t get too many snowstorms or ice storms in the Pacific Northwest, but they are more common than you might think in places like Seattle and Portland. You just need the proper ingredients to come together in the wrong place at the wrong time, and Voila, you have the recipe for winter weather.

Thursday, February 4, 2021

Photographing Snow Crystals - On A Budget



If you have read some of my other blog entries, you know how interested I am in snow crystals.  I have seen some amazing photographs from scientists in many publications, but these guys all have a couple things in common; they usually are connected to some sort of university where resources are endless, and they also put thousands of dollars into sophisticated equipment to get the photos.

Now, don’t get me wrong, I wish I could do that too, but I am on a budget, so I decided to share some of my methods for taking photographs and enjoying nature without spending an arm and a leg.  Over the past few years, I have experimented with much more affordable ways to photograph snow crystals and I think the results have been pretty good as my blog “Mother Nature’s Snow Crystal Workshop” discusses.

I will begin by noting that you need cold weather of course to photograph with any success. If it’s close to the freezing mark and the sun is out, those snow crystals will melt as soon as they hit a surface. At a minimum, I want to outdoor temperature to be at 27°F or colder.  You also want to be watching for tiny flakes falling from the sky. Those big, fluffy flakes you see coming down are not individual flakes, they are made up of hundreds of individual snow crystals. Check out the photo below. This is what is left of one of those half-dollar sized flakes after it landed on my back deck.  I hope this shows how closely you need to look for those beautiful snow crystals.

Setting Up Your Workspace - Don’t Breathe On The Snow Crystals!!

Before we go further into how to view and photograph snow crystals, there are some important ground rules to remember.  First and foremost, in the excitement of looking at a snow crystal, remember that one warm breath can melt that beauty away in an instant. So, be careful to not breathe on them!  Below is my typical workspace, a piece of black felt or fleece on my deck railing. It is being held down by a couple pieces of firewood to keep the fleece from blowing off the deck. 

Prime Weather Conditions

As I noted, I like to work under conditions where the air temperature is at about 27°F or colder.  If it’s warmer than that, it’s tough for the snowflakes to hang around long enough before they begin to melt. I also like to work under calm wind conditions.  Brisk winds can easily break the delicate crystals on their way down to earth, so you end up with a lot of fragments rather than a nice symmetrical dendrite.  If plates or columns are falling, calm conditions aren’t as critical but it helps. Try to photograph on a day when it’s not bright sunshine. I like to get out right after sunrise and sometimes will work at night with the help of a couple of cheap LED flashlights (less than $2) to keep the sun from melting the snow crystals as I collect them. 

Also, be ready to get cold quickly.  Dress warmly for the time you will spend outside.  You will need a thin set of gloves to help maneuver the crystals and your camera to get the best photos.  I can’t tell you how often I step into the house to warm my fingers before heading back out to photograph again. 

Photo Setup 

For my iPhone and camera photography, I normally want to get good contrast between the crystal and the background.  That is why I use my black fleece jacket or a piece of black fleece or felt from a fabric store (Walmart less than $2).

The fleece and felt collects crystals nicely, and since those materials are not perfectly smooth, they can trap the crystals so they do not get easily blown away by even the slightest winds. I have also taken a piece of smooth, clear plexiglass and spray painted it black for a background (total cost ~$4). In calm winds you can get some nice photographs off that smoother surface as well.   However, dark surfaces absorb even more solar energy, so be aware that even if its marginally cold outside, solar insolation, even coming from behind clouds, may quickly melt crystals on those dark surfaces. 

Below are some of the "tools of my trade".  I have a little coni/stamp magnifying glass that I can use to look at snow crystals close-up. However, because my face is so close to the crystal, I must hold my breathe while looking at them. Next is my iPhone with the clip-on macro lens, followed by glass slides for collecting specimens to put under a microscope.  Finally, there is my Olympus TG-6 camera which I use to get some of my best photos. The image below the setup was taken with an iPhone on my fleece jacket.

Almost everyone has a smart phone with a nice camera on it these days and with that little phone you can do a lot. Add a cheap macro lens (~$15) and you can see more. You can then go up to an affordable camera that isn't as much as what the professionals use; typically a Digital Single Lens Reflex (DSLR) camera with macro lenses and extension tubes.  The camera I use now is a reasonable option that’s in the price range of about $350 and has some nice innovations to produce quality photos. Finally, there is a section of photos that I took through my borrowed microscope. If you have a scope, you might want to experiment with that.


I started out photographing snow crystals with just my iPhone, then added a cheap plastic macro lens (about $15) to get a better close-up.  Actually, I was pleasantly surprised by what I could do with a very steady hand and the phone. Steadiness is key to getting a good close-up photo. I have used a little remote (Amazon $5) to shoot with the iPhone so that I would not be holding (and shaking) the camera when I took the photo.  Here’s a photo I took in Buffalo, NY on a very cold day, with the black painted plexiglass, I tinted it blue with GIMP software to get a better effect. Not bad!  

Canon G-12

I love this camera for all it can do in a nice little camera. It not only has full manual capability but it allowed me to get in pretty close for some nice snow crystal photos.  Technology has come a long way since this camera was introduced, but I still use it for all sorts of photos. Here is a look at a photo that captured some beautiful snow crystals up in Buffalo, NY.



After seeing the beautiful photos from Kenneth Libbrecht on his site,  and the thousands of dollars of camera and microscope gear he used to get those photos, I was a bit intimidated, but I still wanted to find a way to do more. I was able to “borrow” a nice, old microscope from a colleague. Now, for professional photographers, this next idea may sound insane, they would use special extension tubes, connectors, filters, etc., to attach a camera to the scope. That would add up to a lot of money but also some pretty decent photographs. I opted for the cheap route. 

I used a rubber connector from a plumbing supply store ($1.68) and mounted my Canon G-12 camera on the eye-piece. Using the “self-timer” on the camera set at a 2-second delay, I was able to photograph the crystals I collected on my glass slides without shaking the camera as I took the photo. I front or back-lit the crystals with 2 small LED flashlights.  Mind you, this is all being done outside, either in my garage (unheated of course) or out on the front porch. Below is an actual photo using the microscope at 10x power and the cleaned up version after I put it into some free photo software (GIMP) and Powerpoint to clean them up and put them on nice backgrounds.

If I am working with a microscope and camera, I like to set my slides out in a shallow box to capture falling crystals, minimizing even the slightest breeze to allow the crystals to land on the smooth slides.  I also put a dark material like black felt inside the box to place the slides on, so it is easier to see the crystals that land on the clear, glass slides.  You have to very careful lifting them out, warm fingers can melt the crystals, and any movement might make the prize crystal slide off the slide.  Below is part of an extensive collection of snow crystal photographs I have made with the microscope/camera setup.  I was pretty pleased with what I have been able to do with the resources I had available.



Olympus TG-6

One of the most difficult parts of macro-photography is that when you are shooting really close to a specimen, it’s very difficult to get things in focus.  Often, a portion of the 3-dimensional snow crystal will be out of focus.  So, photographers use a method called stacking, where they take several photos of the object with tiny adjustments to the focus.  With the help of computer software it will combine these images into one, more fully-focused photo.  Sounds like a lot of work and it is, but wait!!  Olympus, the camera people have just come up with a brilliant idea. They combined that “stacking software” right into their TG-6 camera.  When I heard about that, I immediately went out and bought the camera (Olympus TG-6 $350). It was my biggest investment so far, but I think it was well worth it.  I have not been disappointed.  Below, I have posted several photos of snow crystals I have taken here in the Appalachian Mountains of far Eastern Tennessee with at TG-6 camera. 

Note how nicely focused the photos are.  That stacking technology built into the camera really has helped. I often also use the camera with a small tripod so I can get right up close to the snow crystals and also to keep the camera from shaking. Finally, I again employ the self-timer to keep my finger off the camera while the photo is being taken.

The really great part about taking photos with the TG-6 and the fleece background is that is really gives you a 3-D effect for the snow crystals. It allows then to stand up, rather than lying flat and gives an entirely new perspective to the crystals compared to the microscope photos.  

One of my favorite shots I have taken is the snow crystal suspended off the filaments of an artists brush as shown below.   


Another favorite is this photo taken with the TG-6. I was able to prop the crystal up and the photo looked right through it.

There are many other innovative ideas for taking close-up photographs like these including reversing the lens on a DSLR, and using extension tubes with those more expensive cameras. I likely will be going that route soon.  This hobby can become very addictive and very enjoyable at the same time.  I will leave you with an assortment of snow crystals photographed with my microscope, some of them are strange indeed. See if you can find even stranger ones next time you look closely at snow crystals !!