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February 2024 EZNews

Updated: Mar 19

Hello and thanks for reading the 34th edition of EZNews!

We really appreciate those that have recently joined, renewed their annual membership or signed up for auto-renewal. A special shout out goes out to Lynn B., Dana A. and Hyde R. who all renewed their membership for $100 this past month. We truly appreciate your generosity which helps support our continued innovation and growth moving forward.

For members new to EZWxBrief, you won't find EZWxBrief in the App Store or Google Play Store. For the best user experience, EZWxBrief is optimized to run as a progressive web app (PWA) and must be installed on your device which takes less than 10 seconds per device. Follow the link to the blog post above or see the 140+ page Pilots Guide for more information on how to install EZWxBrief as a PWA on all of your devices. Also check out our playlist on YouTube for some helpful videos on how to use the various features found in EZWxBrief.

Skew-T Weather Essentials live class

With the Weather Essentials for Pilots 12-week class underway, the Skew-T Weather Essentials live class taught by Dr. Scott Dennstaedt is now open for registration! This live 12-week class will begin on Monday, April 15th at 8 pm EDT. Each 60-minute class will be recorded and a private link to the recording will be provided the following day. Therefore, it is not mandatory that you attend each live class to get the most from the course. The tuition for the class is $395. The class is already two-thirds full, so register today to reserve your seat!


This class is less about learning how to use the Skew-T log (p) diagram and more about learning the fundamental principles and building blocks of aviation meteorology. The tool makes for a great canvas or backdrop to teach you about what causes the formation of clouds, fog, airframe icing, turbulence, and thunderstorms, just to name a few. In other words, you need to understand these basic principles of weather first, before mastering how to interpret the Skew-T log (p) diagram for your preflight weather planning and analysis.

The class will finish on Monday, July 1st with one additional class reserved on July 8th in the event of illness, travel and/or spillover. For this class it is recommended that you purchase a softcover or digital copy of The Skew-T log (p) and Me: A Primer for Pilots. It will be the text used exclusively in class for reading assignments.

"Who's who in Aviation & Weather" YouTube series continues...

We had a great time chatting with Max Trescott of Aviation News Talk in our latest "Who's Who in Aviation & Weather" series. You can view this 30 minute video with Max. Max has been a flight instructor for over two decades and was the 2008 National Flight Instructor of the Year. He has written three books and is the host of the Aviation News Talk podcast. He's a wealth of knowledge and has a humble attitude about flying in weather.

This YouTube program will bring you the latest news and insights from the top minds in the aviation and weather industries. With a focus on weather, each month we'll feature interviews with leading experts on topics such as air traffic control, flight safety, forecasting, flight instruction and more. We'll also explore the latest trends and developments in these fields, and provide you with the information you need to stay ahead of the learning curve. So join us every four to six weeks as we explore the latest news and trends in these two fascinating industries.

Stay tuned for our next live program on Thursday, February 8th at 2 pm EST. We are very excited to be talking with Julie Boatman editor-in-chief of FLYING magazine to get her perspective on how the media plays a roll in the aviation industry.

On the schedule for this spring, we'll be talking with Rod Machado on Tuesday, March 12th at 2 pm EDT. We'll also be talking with other industry experts this year to include Mark Robidoux of and Matt Johnson, a helicopter pilot and DPE.

> How to watch <

The program will be hosted live on EZWxBrief's YouTube channel. If you cannot attend live, the episodes are recorded and will become available on the same channel shortly after the live broadcast ends. You can also find them in the Who's Who in Aviation & Weather playlist. The exact date and time for future episodes will be announced through this blog and will appear on the EZWxBrief YouTube community page.

Is flying through snow an airframe icing risk?

There are many opinions in the aviation community that flying through snow is not only an icing hazard, but also against Federal Aviation Administration (FAA) regulations for aircraft without a certified ice protection system. Keep in mind, that each weather system is unique and there are many exceptions to the general discussion presented here. Let's discuss some of the factors associated with flying through snow.

Snow falling out of the base of a cloud means that there are fairly deep saturated conditions aloft. To produce snow typically requires that the cloud top temperature (CTT) be sufficiently cold. That usually means a CTT of -12 degrees Celsius or colder - colder is often better. In this situation, ice crystals can develop and lead to the development of snowflakes in the cloud aloft. If you are flying through snow below the cloud base, does that imply icing conditions exist? Just to be clear, this is not a discussion of flying in the clouds that are producing the snow, but below the cloud base.

Snow is considered visible moisture. It can be mixed with other precipitation types that may include rain, freezing rain or ice pellets. In general, snow falling from the base of a cloud doesn't represent a significant airframe icing hazard unless it is mixed with other types of precipitation such as freezing rain. It can be an issue with induction icing, but not airframe icing. In the unlikely case that snow does adhere to the airframe, an exit plan should be executed.

Outside of a mixed precipitation scenario, snow is usually classified as wet or dry. Wet snow occurs when the static air temperature is at or above 0 degrees Celsius. That is, the snow falls into an atmosphere that is warmer than freezing and begins a melting process. Although liquid water doesn't necessarily freeze at a temperature below 0 degrees Celsius, it is the case that snow must begin to melt at a temperature warmer than 0 degrees Celsius. If the temperature is warm enough, it will completely melt the snowflake into a raindrop before reaching the surface. You may have experienced this in your car. You'll see the wet snowflake splat on your windshield and quickly melt. Wet snow can begin to accumulate on grassy surfaces or other vegetation, but usually melts quickly on other surfaces.

Moreover, because you are flying at an airspeed where kinetic heating occurs on the leading edge, even at a static air temperature of 0 degrees Celsius, snow will typically not accrete on the leading edges of the wings and horizontal stabilizer due to this kinetic heating that is driven by adiabatic compression. This is typically referred to as ram air rise. And certainly, with a static air temperature above 0 degrees Celsius, it is very unlikely to accrete with the additional ram air rise. In fact, even at a static air temperature of -1 or -2 degrees Celsius, accreting ice is typically difficult at best. Once the static air temperature gets colder than -3°C, then you are no longer dealing with wet snow since no melting is occurring.  

Certainly, wet snow can be problematic while taxiing. Or, if you pull your airplane out of a warm hangar, even dry snow will melt and begin to collect on some surfaces and may accumulate over time. It is recommended that you never depart with any of the aircraft surfaces contaminated to include wings and the horizontal stabilizer. Doing so, may cause the aircraft not to develop the lift necessary to takeoff and climb creating a risk of impact with terrain.

Another metric to use is the Current Icing Product (CIP) found on the Aviation Weather Center website, CIP utilizes a recent three hour forecast from the Rapid Refresh (RAP) model for parameters such temperature, moisture aloft, supercooled liquid water content and other useful model data. This is mainly to "seed" the forecast for these items given that observational data is rather sparse throughout the atmosphere for these important parameters. Nevertheless, it combines this with surface observations, ground-based radar, pilot weather reports, satellite imagery and lightning to produce an hourly analysis of icing probability, icing severity and supercooled large drop icing potential from the surface through 30,000 feet. 

CIP looks for information about the presence or absence of six precipitation types that include freezing rain (FZRA), freezing drizzle (FZDZ), ice pellets (PL), rain (RA), drizzle (DZ), and snow (SN). A report of any of the first five precipitation types means that altitudes below cloud base need to be considered for possible icing and SLD, because subfreezing liquid precipitation may be present. However, an observation in which only snow is reported at the surface, ice crystals are clearly present beneath and within the lowest cloud layer and those are not considered an icing threat especially below the lowest cloud base.

For example, if an airport is reporting an overcast sky at 2,500 feet and only snow is being reported, the algorithm in CIP will remove any possible occurrence of icing from the cloud base down to the surface regardless of what other sources may say. This because snow that is not mixed with other precipitation types such as freezing rain is not seen as an icing hazard...even wet snow. 

Is it legal to fly through snow in an aircraft without a certified ice protection system? First you may want to read this letter from the FAA's Office of the Chief Counsel. The essence of this letter states…

"The formation of structural icing requires two elements: 1) the presence of visible moisture, and 2) an aircraft surface temperature at or below zero degrees Celsius. The FAA does not necessarily consider the mere presence of clouds (which may only contain ice crystals) or other forms of visible moisture at temperatures at or below freezing to be conducive to the formation of known ice or to constitute known icing conditions. There are many variables that influence whether ice will actually be detected or observed, or will form on and adhere to an aircraft. The size of the water droplets, shape of the airfoil, and the speed of the aircraft, among other factors, can make a critical difference in the initiation and growth of structural ice."

Yes, snow is visible moisture, but will it adhere to the airframe? Dry snow is not going to adhere to the airframe. Wet snow as mentioned above is more of an induction icing or ground icing concern than airframe icing while in flight.

Sometimes it's not about airframe or induction icing. Flying through falling snow can also be very disorienting at times especially when the snowfall is moderate or greater or you are flying at night. It will often lower flight visibility to 3 statute miles or less and can make runways extremely slick. Landing while it is snowing on a snow-covered runway can lead to a flare at an altitude higher than normal making for a hard landing.  


One last point. Often when snow falls into a fairly deep dry layer below the cloud base it can sublimate on its way down. This usually occurs with the onset of precipitation as a weather system approaches. Evaporation and sublimation are both cooling processes and that will lower the temperature of the dryer air. What may be an atmosphere that is a few degrees above freezing that can lead to melting wet snow, cool temperatures created through this process can quickly move the temperatures to below freezing allowing for snow to reach the surface instead of melting.

We are really excited about being chosen this year to participate as an exhibitor in the inaugural Innovation Showcase. This will be held at the 50th annual SUN 'n FUN event in Lakeland, Florida. This means that EZWxBrief will be highlighted as a product that has contributed to safety within the aviation community for its unique and innovative approach to preflight planning.

We will also be holding multiple presentations at the Future ‘n Flight Forums tent that is reserved exclusively for Innovation Showcase exhibitors. We will be in booth # 20 in the Innovation Showcase tent located in the Future ‘n Flight Plaza. If you are headed to SUN 'n FUN this year, please stop by and say hello and get a demo of EZWxBrief or attend one of several presentations by Dr. Scott Dennstaedt. Details of the presentation schedule to follow in a future EZNewsletter.

EZWxBrief v2.0 update

The testing for EZWxBrief v2.0 is going well and we expect to release within the next eight to ten weeks. Meanwhile, with this version you will see a new feature called the EZWxBrief Dashboard. This will provide a birds-eye view of your current preflight weather planning by providing access to recent routes, recent airports and recent imagery. You can also access your saved items and see all of your settings that include the personal weather minimums. From the Dashboard you can also plan a new route. The Dashboard can be chosen as the primary landing page every time you sign in and will be a portal into the app.

We appreciate your patience and look forward to showing the world EZWxBrief v2.0 very soon.

Most pilots are weatherwise, but some are otherwise™

Dr. Scott Dennstaedt

Weather Systems Engineer

Founder, EZWxBrief™

CFI & former NWS meteorologist

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