Rotor Clouds and Cold Legs
2007-02-11 08:37:48.000 – Neil Lareau, Observer
Rotor Clouds
Jon Cotton looks at me and says “Jonny Cotton is losing much heat.” Iconcur and we retreat to the relative calm in the lee of the generatorshed. To the east an elongated roll of benign looking cumulus occupies thesky above the Carter-Moriah and Wildcat ranges. Closer inspection revealsa more insidious beast, a rotor cloud, a tumbling eddy the top of which ismarked by heaps of miniscule cloud droplets. Along the upper fringe ofthis cloud a thin veil of pileus can be seen, suggesting the interactionof this rotor (eddy) with the laminar flow directly above it. To the northa thin cap cloud (stratocumulus standing lenticulars) is shrink wrapped tothe form of Mount Jefferson, a peak which above all others in this rangeencourages the formation of such clouds. The cirrus and cirrocumulus highoverhead suggest a few ripples of orographic waves. Over the ocean lowclouds mimic the subtle ridge silhouettes characteristic of eastern mountains. Soon thesun will rise into the scene, and we will rejoice. It has been a whilesince we’ve seen the sun, and today especially as the morning wind gnaws at the backof my knees (and apparently does the same to Jon), the warmth of thatmassive fire ball is going to feel good.
Mornings like these go a long way toward washing away the monotony of fog;grey on grey on white. This dawn also reminds me of why I love this place;the dynamic interaction of air and mountains.
All the fine photos you see here were shot by Jon Cotton.
Edutrippers waiting for the sun
Neil Lareau, Observer
Supporter Spotlight: Angelo Decrisantis
Supporter Spotlight: Angelo Decrisantis By Wendy Almeida For Angelo Decrisantis, Mount Washington has been a lifelong connection. It began in 1965, at age 15, on a family drive to the summit. “My first experience
2025 Holiday Gift Guide
2025 Holiday Gift Guide By Brandi Malloy There’s something magical about Mount Washington, especially during this time of year. Thanks to our online store, you can bring a little piece of that magic home—
Supporter Spotlight: Emory Prescott
Supporter Spotlight: Emory Prescott By Wendy Almeida For Emory Prescott, being a Mount Washington Observatory member for the past 10 years isn’t just about weather. It’s about purpose and the kind of research that




