Occam’s Razor – the simplest explanation is most likely
People ask me to look into weird things all the time. Since I operate a weather business that specifically offers weather radar analysis and tracking software, I got asked to look at this image from a Daily Mail article which claimed: Weather experts baffled by mystery plume on New Mexico radar near 1945 nuclear bomb test site
An animation of the plume follows:
I’ve seen images like this dozens of times before.
It is very likely a large swarm of birds taking off. The first two frames are the giveaway. When birds take off from the ground, they are tightly packed from their feeding/roosting area. When they go aloft, they immediately spread out, and that is exactly what we see in the first two frames of the animation. Compare it to Figure 2 in the article below and the animation below and you’ll see what I mean.
Our sensitive NEXRAD WSR-88D Doppler Weather Radar network is routinely capable of picking up bird swarms like this, something we couldn’t see with older WSR-57 and WSR-74 weather radars. The NEXRAD system can also pick up bugs and bats that exhibit typical swarm behavior. We’ve all seen huge swarms of birds that blot out the sky, so of course they can be picked up by weather radar looking for rain, since birds, like humans, are mostly made up of water.
It could also be insects, such as these examples:
Weather radar catches massive bug swarm
A vast swarm of bugs that covered much of the northern half of the North Island last night and this morning has been caught on the Metservice weather radar.
MetService didn’t know what it was and entomologists were puzzled.
And: A huge hatch of mayflies on radar:
Bird Detection via Doppler Radar
Angie Enyedi (radar animation by Jason Deese)
National Weather Service Jacksonville
Doppler radar transmits pulses of energy into the atmosphere, and when this energy intersects a target, information about the density (radar reflectivity) and motion (radar velocity) of the target is transmitted back to the radar (Figure 1). Most of the time the Doppler radar beam intersects targets composed of water vapor, including clouds, rain drops and hail stones. Meteorologists utilize this data from the radar to interrogate storms, which makes the Doppler radar a critical component of the proactive severe weather warning service that the National Weather Service (NWS) provides.
Sometimes, the radar beam intersects other objects, including birds. When there is a high density of birds in one location, typically during bird migrations, sometimes as the birds take flight the radar beam intersects the flock. This happened in several locations across coastal Southeast Georgia on the morning of October 25, 2009, right around sunrise. This is a favored time for birds, particularly waterfowl, to leave their nocturnal nesting sites on bodies of water to either continue their migration or return to their favorite daytime refuges.
The animation (Figure 2) illustrates two large and one smaller area of birds taking off, as detected by the NWS Jacksonville Doppler radar. In addition, there is a Google Map (from Google Earth) to reference for location (Figure 3). It appears as though the southernmost flock arose from the Satilla River near Woodbine, while the other flock ascended from a tributary of Buttermilk Sound, just west of Little St. Simons Island. A third, but smaller flock, appears to have flown from the western side of Cumberland Island National Seashore.
Many bird enthusiasts utilize radar imagery to track migration patterns. Radar imagery has also been helpful to both birds and humans regarding aviation safety. Most airport terminals use radar data to track birds as they cross flight paths to avoid collisions.
Click here for more information on the NWS Doppler Radar.
UPDATE: For those of you who say bird swarms can’t be that big…
Reader JohnS notes:
Submitted on 2014/03/19 at 4:05 pm
The playas at 34.655294° -105.900141° might be good candidates for a starting point, since they are probably wettest around this time of year. Note the line of bird choppers to the south.
REPLY: Good candidate, here is the satellite view, clearly a seasonal wetland: http://maps.google.com/?ll=34.759666,-105.867004&spn=2.008193,1.972046&t=h&z=9
Windsong says: March 19, 2014 at 3:36 pm
Large flocks migrating at night quite common in my area. Some interesting images here: http://cliffmass.blogspot.com/2013/09/mega-bird-migration.html
I’ve reproduced the relevant parts from Cliff Mass, who writes:
Starting with the radar image (composite of all altitudes) at 7:49 PM Saturday night, we see a lot of ground-clutter returns (the lower radar beams hitting the surface mainly).
About an hour later (9:09 PM) and after sunset, things have really changed. Lots of echoes and some very intense. These are the birds. Birds don’t like to migrate offshore very far and you can see that in the echoes.
12:22 PM the echo coverage has expanded. Lots of birds on the move
5:37 AM there are still some birds, but the numbers are dropping.
And after sunrise at 6:39 AM, nearly all are gone and we are back to ground clutter
The Langley radar is a Doppler radar and it gives the velocity of the targets (in this case birds) towards or away from the radar. Here is the Doppler image at 12:46 AM. Green indicates approaching and red and orange going away. Clearly the birds are heading south!
Now let me show you something interesting. Here in Seattle we have a very special type of weather radar, called a radar-wind profiler, located at the NOAA facility at Sand Point. Instead of sweeping horizontallly, this radar has three static beams, mostly facing upwards. This radar picks up birds as well. Take a look at an image from this radar for the 24-h ending mid-day Sunday. The y-axis is height in meters and time is on the x-axis (in Greenwich Mean Time (GMT, UTC), 06 is 11 PM, 12 is 5 AM, etc.). Stronger returns are in purple, blue, and green. The birds are obvious. Around 03 UTC (8 PM) we we see the start of the bird echoes. Lots of flying in the evening, which fades a bit in the middle of the night. But you see a complete collapse after 5-6 AM as it starts getting light out.