Report

Author: Chris Davidoff

Assignment: Clouds First

Cloud Type: 1) Altocumulus 2) Altostratus

Date:  09-04-2018

Time: ~3pm

Location: Boulder, Colorado – Looking over ‘Lost Gulch’

In this first cloud assignment, I captured a time lapse of what I believe to be a Foehn cloud system developing over the front range.  The clouds were turning into altocumulus and altostratus as time went on.  I shot this at Lost Gulch, just 15 minutes up baseline road here in Boulder,CO.  Originally, I was facing west and was shooting a time lapse of Altostratus clouds.  It wasn’t very interesting and I kept looking over a very cool development happening to the north.  Eventually I caved into changing my camera direction and began a new time lapse that focused on this new Foehn cloud wall.

These time lapses were taken at a place called Lost Gulch.  Lost Gulch is a beautiful location just up ‘Baseline’, here in Boulder, CO.  It overlooks a grand valley to the west, and to the north you can see start of the Rocky Mountains.  This is where the first time lapse in the video takes place, looking over that first set of mountains (North).  My camera was angled at a 20 degree angle to capture this.  It was a gorgeous end-of-summer day, between the times of 1-4pm.

Below is the SkewT plot for the day I shot these clouds: (pulled from University of Wyoming)

The temperature of the day was found to be:

(pulled from www.weatherunderground.com)

The first half of the video has clouds at ~10,000ft.  The 2nd half are more towards ~15,000ft judging by the SkewT.  The atmosphere was pretty stable so there were no thunderstorms building either.  It’s pretty hard to use sounding data to predict weather over the mountains, because the mountains themselves cause a great deal of disturbance in the atmosphere.  This is why we can see so much activity accruing over the mountain.  You can’t see it, but just to the east (over the plains) it was all sun.  Regardless, the sounding data seems to have accurately depicted the height in which the clouds were at which is really cool.

The time lapse spans about 2 miles on the horizon.  The clouds themselves were about 3 miles away.  My camera and image specs were as follows:

• D850 (digital)
• 55mm\f1.4
• ISO 64
• Shutter speed 1/1250
• 4000×3000 pixel resolution

I created the timelapse by using the electronic shutter mode on my camera.  This allowed me to take thousands of photos without wearing down the physical shutter.  All of these photos were imported into a program called ‘Machspeed’ which allowed me to string the photos together into a video.  From there, I imported the videos into ‘Davinci Resolve 15’ which is a wonderful and free video editing program.  I browsed for free stock music and eventually came up with what you see in the video.  If I did it again, I would use a different timelapse-ing programing because it kept compressing my photos and making it look pixelated.

In the end I was mostly happy with my video.  There are a few frustrations.  The 1st shot in the video was actually captured last.  This was because I originally started with the 2nd shot, hoping something interesting would happen.  After 1.5 hours, nothing cool had developed, yet there was an interesting system happening to the north (the 1st shot).  Eventually I moved the camera, but I then didn’t have enough time to get the length of video that I had wanted.  Otherwise, I thought my timing was good and showed the evolution of the clouds well.