Wednesday, March 23, 2016

Reporting useful weather observations on social media

In the mid-south severe weather is a major topic of discussion in the spring.  The seasonal warming causes atmospheric instability leading to high winds, heavy rainfall, hail, and tornadoes.  No one can disagree that in order to be prepared you must be informed.

There are so many ways to stay informed about severe weather. You could watch the local news stations, or get some "insider information" on blogs written by experts (such as the Arkansas Weather Blog by my friend Todd Yakoubian).

If you really want the raw data without any explanation or corroboration, you could listen to Skywarn weather nets on amateur radio.  In central Arkansas we have the AR Links Skywarn net, which can extend to cover the entire state, and the CAREN Skywarn Net which covers several counties in central Arkansas.

Even if you don't have an amateur radio license, you can help save lives and property during severe weather by sharing what you see where you are.  Being a weather spotter does not involve chasing a tornado or sitting in your car streaming hail stones online.  All it takes is sharing reportable criteria from right where you are.  Reportable criteria is the term used for the specific clues used by meteorologists that can tell them if a storm is strong, weak, or changing in strength.

How to share weather actionable information on social media

Where ever you are, you can help keep meteorologists supplied with relevant, timely, actionable information by sharing what you see on social media.  In order to ensure your observation can be useful, there are a few tips you should follow.

  • Use the appropriate hashtag.  Hashtags make it easier to locate posts that are about the same topic.  In Arkansas we use #ARWX, which is short for "Arkansas weather".
  • Include your location.  On most social media web sites and apps you can add your location with just a click.  Be sure to familiarize yourself with that option before you need it.  By including a specific location, your report goes from "interesting" to "actionable".
  • Don't share or retweet old reports.  Remember the boy who cried wolf?  We would never want that to happen during severe weather.  If someone posted a tornado warning 2 hours ago, don't retweet that now.  Some people may not see that it's old news.  The next time they may think it's old news again, and the unthinkable could happen.  Don't share or retweet old reports.
    • Be cautious of photos shared from unknown sources.  A couple of times every year, someone digs up a photo from a weather event that happened months or years earlier and tries to pass it off as their own.  The best advice is to consider the source.  There are ways to verify photos, but that will have to wait for another post.
  • Be sure to include an accurate description (include a photo or video if safe to do so), and post reportable criteria.  
Which leads us to the most important part of reporting weather observations...

When to speak up or When to shut up

There are key pieces of information that can help meteorologists and first responders, we call these reportable criteria.  If everyone were to get on the various Skywarn radio nets and report that "it's not raining here yet", then the one person who is looking at a funnel cloud won't be able to be heard.  Likewise, if everyone on Twitter shares "The sky looks scary in Conway. #arwx", it would be difficult for officials to see any urgent reports.  Here are the reportable criteria for severe weather.

Tornado or funnel cloud

A tornado is a violently rotating column of air, attached to a cloud structure overhead, and touching the ground.  If it is not touching the ground, then it is a funnel cloud.  Sometimes you might not be able to see where it touches the ground, so look for flying debris at the lowest point you can see.  If you can identify debris, it is probably a tornado.

Before reporting a funnel cloud or tornado, review this checklist:

  1. Are you in a favorable location? (Are you in the southwest corner of a super-cell or southeast corner of a High Precipitation (HP) super-cell?)
  2. Are you in an inflow area? (As you look into the feature, is the wind blowing into your back?)
  3. Is the cloud feature attached to the base of the thunderstorm?
  4. Is the cloud feature rotating? (Spinning like a figure skater or a toy top, normally from left to right, not up and down like a rolling pin.)
  5. Is the rotating feature persistent? (continuing for several minutes)
If you aren't sure about one of these, go ahead and report it, but state the item that you aren't sure about.
"I think I am looking at a funnel cloud. It is southwest of the main storm, attached to a thunderstorm above it and descending from it.  It is spinning, but it is not straight up and down.  It is almost at a 45 degree angle from the ground."
This would give the other party enough information to investigate it further.

Wall cloud

A wall cloud is attached to the base of a thunderstorm and hangs down underneath it.  Sometimes a wall cloud can be seen rotating, but not always.

Wind damage

Any wind estimated to be 50 mph or more should be reported.  With using an anemometer, you can estimate wind speed by observing nearby trees.

  • 25-31 mph - Large tree branches moving. Wires whistle.
  • 32-38 mph - Whole trees moving. Inconvenience walking into the wind.
  • 39-46 mph - Small branches or twigs break off. Impedes walking.
  • 47-54 mph - Slight structural damage (shingles blown off). Large branches break off.
  • 55-63 mph - Structural damage (parts of roofs blown off). Trees snapped off. 

Hail

On social media, feel free to report hail of any size.  However, only hail that is the size of a US quarter (1") is reportable criteria.  Ham radio operators should never report anything smaller than a quarter.

Flooding

A flood is water rising rapidly, flowing over roads, or into buildings.  Be sure not to confusing pooling and flooding.  If the rain were to stop right now, and the water would be gone in seconds, it is not a flood.

Protect life and property

By becoming aware of what information is actionable, and the various methods that can be used to report it, you are a step closer to being a small part of a large solution.

The National Weather Service offers free classes that will make you a certified Skywarn Storm Spotter.  To find a class in your area, visit http://www.nws.noaa.gov/skywarn/skywarn.htm.

If you have any questions about severe weather or reporting procedures, feel free to send me a message on Twitter at @Joshua_Carroll.



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