Mount Washington
Mount Washington on the 4th of June
The summit of Mount Washington in New Hampshire was coated in nearly an inch of snow and rime ice earlier this week as winter weather continued during what some are calling "June-uary."

"Rime ice is not rare in June, but I wouldn't say it's common either. It's not abnormal to have it once or twice early in the month. Rime ice forms via a process known as deposition, the direct phase change from water vapor to ice crystals," said AccuWeather Meteorologist Brett Rossio.

On Tuesday morning, observers on Mount Washington reported that 0.9 of an inch of fresh snow had accumulated since Monday morning. In addition to the snow and ice, fierce winds were recorded. A 102-mph wind gust was reported Monday night. The mountain, with its peak reaching an altitude of 6,288 feet, is the tallest mountain in the northeastern United States and is notorious for experiencing wild weather.


"Mount Washington is exposed to cloud cover all the time. In fact, the summit is "in the clouds" around 70% of the year. When tiny "cloud" water droplets are suspended in the air and the temperature is below freezing, they are known as, "supercooled water droplets," said Rossio, who previously worked at Mount Washington as an intern.

Rime ice occurs when super-cooled droplets freeze and attach onto an exposed surface. All objects impacted need to be at 32 F or below, causing the liquid to freeze instantly.

"When these droplets make contact with various objects, they spontaneously freeze and form into rime ice. Rime ice is opaque and appears cloudy/milky in color," Rossio said.

"The process of super-cooled water droplets making contact and accumulating with either aerosols or ice crystals (heterogeneous or homogeneous nucleation, respectively) is known as accretion," Rossio said.

In extreme cases, rime ice can accumulate over a few days and weigh down trees, power lines and communication towers and cause damage.

"Weather observers on Mount Washington frequently have to clean the rime ice off the weather instruments as they can accrete significant amounts of supercooled water droplets," Rossio said.