National Wind Turbine Map: A new Pilot Resource

As one of the fastest growing forms of renewable energy, wind turbines are sprouting up all over the country.  On a recent airline flight across the country, I was blown away to see areas in northern Texas with rows of wind-turbines that went on for miles—some of which included well over of a hundred turbines. Now I know why they call them wind farms!  This technology is increasingly popular in rural Alaska, where the cost of fuel to generate electricity is through the roof expensive.  As with all good things, they come with potential impacts.  As pilots, wind turbines provide several challenges: initially as obstructions we have to avoid during flight.  If located too close to airports, they interfere with instrument approaches resulting in higher minimums and reduced access.  Finally, when the wind  blows they represent a source of turbulence, which we still have much to learn about (more on that later).

Interface to the Interactive Wind Farm Map, starts with an overview of where towers are found around the country.

Interface to the Interactive Wind Farm Map, starts with an overview of where towers are found around the country.

Locating individual wind turbines
Recently the US Geological Survey has given us a new tool to locate wind turbines, on a nation-wide basis.  A new interactive mapping application, provides access to a database that not only shows us where wind turbines are found, but records their height, blade length, and other information on a tower-by-tower basis. Prior to this, while some states captured the locations of individual wind turbines, there was no uniform database that provided this information across the country.  Starting with the FAA’s Digital Obstruction File (through July 22, 2013), a USGS team led by Dr. Jay Diffendorfer located over 47,000 turbine sites, verifying individual tower locations with high-resolution satellite imagery. This data base gives us a much better way to find individual tower locations, with a location accuracy estimated to be within 10 meters.

While fewer in number, wind turbines are sprouting up across Alaska.

While still few in number, wind turbines are sprouting up across Alaska.

A row of wind turbines just outside Unalalkeet, on the west coast of Alaska. According to the USGS interactive map, they have a total height of 156 ft. tall

A row of wind turbines just outside Unalalkeet, on the west coast of Alaska. According to the USGS interactive map, they have a total height of 156 ft. tall

Understanding impacts
This database is designed to support research into environmental effects on both critters that fly, and wildlife habitat.  But these data may also be useful in the future to project the impact of down-wind effects on general aviation airports, which is still an evolving research topic.  A recent study at the University of Kansas has shown that the turbulence from a wind turbine extends further as wind speed increases, up to 3 miles in some cases.  This and the potential increase in cross winds could be a significant impact for small aircraft at GA airports.  Hopefully, more work will be done to quantify these conditions, leading to improvements in the FAA’s obstruction review process, which today only takes into account the height of an obstruction above ground when air space reviews are conducted.

Provide feedback
All maps are only as current as the date used to make them.  This data set incorporated information from FAA’s obstruction file as of last July.  And if you come across wind turbines that aren’t in the database, please capture what information you can and send an email with the location to jediffendorfer@usgs.gov.

Thanks to this effort, we have a better way to learn where wind turbines are located in the areas where we fly!

Alaska Aviation Weather Forecast Changes and Enhancements

Update:  Due to the government shutdown, the changes described below have been delayed, and are planned to go into effect on November 12.

The weather is still one of the most important factors we need to evaluate before each flight.  Whether you fly VFR or IFR, knowing the current conditions and how they are expected to change is critical to that all important GO/NO GO decision,  figuring out which route to take, and what to watch for inflight.  On October 15th, the Alaska Aviation Weather Unit (AAWU) will make changes that should help you make those decisions, as you plan to fly.  Here are some of the changes.

Area Forecast/Airmets
Starting in mid-October, new Area Forecasts (FA’s) will be issued three times a day—at 4:15 a.m., 12:15 p.m. and 8:15 p.m., local Alaska time.  Updates will come out at 12:15 a.m., 6:15 a.m. and 6:15 p.m.—or as needed if things are changing faster than anticipated.  AIRMETs will be either issued or updated using a similar schedule, the details of which may be found on the AAWU website at: aawu.arh.noaa.gov/changes/

Icing and Turbulence Graphics
In a trend which I find helpful, more information is being presented in graphic form.  Starting on Oct 15, the AAWU will issue new icing and turbulence graphics, showing the forecast in three-hour time slices, as opposed to the 6 hour charts we have been using.  Found under the Graphical Forecast tab on their home page, in the sample Icing Forecast product below, the user has a choice of viewing a single 12 hour summary, or on the bar immediately above the product, selecting one of the three-hour charts to see how the forecasters expect conditions to develop during the day.

Sample Icing Forecast Product summarizes over the entire 12 hour period. Individual charts showing 3 hour intervals show how conditions are expected to develop.

Sample Icing Forecast Product summarizes over the entire 12 hour period. Users can select individual charts showing 3 hour intervals to see how conditions are expected to develop.

Another change is that the Turbulence Forecast will be split into separate low and high altitude products.  Along the top, in the sample image below, the user again has the option to look at the 12 hour summary— showing the entire forecast period—or can mouse-over a progression of graphics to see how the turbulence is expected to develop during the forecast period.  Note that while the products are split at Flight Level 180, if conditions span that flight level, they will be depicted on both sets of products.  A little time spent examining the legend to become familiar with the new conventions will help become accustomed to these products.

sample turbulence lo level

Sample low altitude turbulence product, covering a 3 hour period. Users may also select the 12 hour summary chart to get the “big picture.”

A more subtle difference in the product to note:  An additional turbulence category, “Isolated Moderate” is being added. Previously the products only depicted “Occasional Moderate” and “Isolated Moderate to Severe” conditions.

table 2 issuance times

Table showing when both graphic and text products will be updated. Helpful if the weather is bad and you are waiting for the next forecast!

Other graphic products, such as the Surface Map and IFR/MVFR Chart won’t change, however the issuance and update times will.  The AAWU has provided a table (above) summarizing the timing of both text and graphic product which provide a roadmap to the new scheme.

These are significant enhancements to the products available to Alaskan pilots, and a downloadable document summarizing them is available online that contains examples and a more complete description of the schedules and changes.  If you have feedback on products, the National Weather Service would like to hear it. An easy way to reach them is to shoot an email to mailto:nws.ar.aawu.webauthors@noaa.gov.

As pilots we need to remember that the accuracy of these products is influenced by the PIREPs we file, either confirming forecast conditions, or alerting forecasters when conditions are changing faster than expected. Please take time to file an extra PIREP or two as you fly.

So a modification to an old adage might be… “If you don’t like the weather you see at the moment, just wait for the new forecast.”  Thanks to these changes, the new forecasts will be showing up more graphically and more frequently than before.