Sun pillar over Manitoba, Canada
© Steinbach Online
Many people in Steinbach have noticed some unusual light phenomena in the skies over the past couple of days in the form of sun dogs and sun pillars.

Local meteorologist Scott Kehler explains that sun pillars are a vertical beam of light moving away from the sun while sun dogs are little arcs that appear on either side of the sun. Despite their difference in appearance, Kehler says these events are connected.

"They both tend to be related to ice crystals in the air, though the way they are produced is a little bit different. From my recollection, sun pillars occur when the sun is lower in the sky and the sun dogs happen when it is higher in the sky."

Kehler indicates that the conditions for either of these phenomena to occur are quite specific. "Something a lot of people don't realize is that liquid water can actually exist in the atmosphere up to minus 40." This means that ice crystals only really begin to form in significantly colder weather.

Sun dog over Manitoba, Canada
© Steinbach Online
Kehler notes that clouds also hinders these kinds of events. "On a cloudy day, you usually wouldn't see them for two reasons. One, cloud cover generally means it is warmer outside and two, you need a fairly bright sunshine in order to produce these kinds of things."

Kehler indicates that the prime temperature for this kind of light refraction is between -30 and -40. However, if the weather warms up again, as the forecast suggests, this may have been one of the few possible opportunities to glimpse sun dogs or sun pillars that people will get this winter.

Light events including sun dogs, sun pillars, and rainbows all fall under the study of atmospheric optics which is concerned with the way light interacts with the atmosphere.

As an aside, Kehler shares his favorite fun fact about atmospheric optics: "A lot of people have seen double rainbows before, but next time you see one look at the colors, because the colors on the second rainbow are actually reversed." According to Kehler, a typical rainbow is the result of light passing through a water droplet once, whereas a double rainbow means that light is passing through the droplet twice which flips the colors.

Kehler adds that he has never before seen a double sun dog and is fairly certain that ice crystals cannot refract light in that way.