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Amelia,
I've never flown over large bodies of water, so can't comment on that. The snow here in the Rocky Mountain region is very dry--powder snow. As long as you are above minimums, you can fly through snow in instrument conditions. Once, flying from Sierra Vista, Arizona (near Mexico), back here to Denver, I entered snow flurries over northern New Mexico. The air was stable, the snow wasn't accumulating on the wings--it was just, well, snowing outside. If you've ever driven in blowing snow where the snow doesn't accumulate on the windshield of the car, it was like that. I just continued the instrument flight, with frequent ice inspections of the leading edges of the wings. That's what the ice light is for. I didn't get out of the snow until final approach at the airport. Now, wet snow may pose a different problem and may cause some icing.
Icing is something to avoid. I had planes certified for flight into 'known ice' conditions, and still avoided ice whenever possible. If there's anything that can ruin the airfoil effect of the wing, it's ice. It accumulates on the leading edge of the wing. Two forms are generally recognized, rime ice and clear ice. Ice forming on the wing has two negative effects--it disturbs the airflow over the wing and it adds weight to the plane (clear ice). It can occur in summer or winter if flying high in moist, cold conditions. Though it isn't snowing, the wing gets extremely cold, and moisture turns to ice gradually on the ice-cold wing. That's rime ice. Clear ice tends to happen fast when you inadvertently fly into freezing rain or ice. That's a scary proposition.
In the Mooney, flying below the cloud tops at about 9000' just north of Telluride once, it was raining and there were thunder cells ahead on the radar. I asked for a report from the commercial turbo-props on the 'tops' of the cells. One reported that the tops were from 19,000 to 20,000ft. I asked Denver Center for a clearance to FL210 to get above the weather. Everything was fine until about 19,000ft., though it continued to rain. In about 30 seconds or less, the plane was thrown up to 22,000'. At the same time, I lost all forward visibility as the plane was suddenly covered in clear ice. The windscreen was a solid sheet of ice, and clear ice suddenly appeared on the leading edges of both wings. When the ice hit, it sounded like the plane was being sandblasted or hit loose gravel--it was noisy. Then the noise stopped and I was left flying a popsicle. I never found the cloud tops. The plane was hard to maneuver and I couldn't hold a heading. The engine began to sputter (iced over ram-air portals in the cowling), and I pulled the alternate air lever. Alternate air didn't change a thing, and I noticed that I had turned 90deg north and was losing altitude. The controls were getting heavy and washy. I informed Denver Center of the problem and was able to gain some control with increased airspeed during the emergency descent. I headed for the lowest airport around--Montrose, Colorado. Fortunately, icing doesn't affect the radios much. Below FL180, I cancelled IFR and told Denver Center I should be OK once I got the plane into warmer air. At about 10,000ft, I was again out of the clouds, and the Montrose airport was in sight. As soon as the OAT rose above 32 degrees, all of the ice on the plane melted, the wings cleared, the engine stopped missing, and I leveled off. I then finished the trip to Denver by flying under the clouds through Monarch pass. So, ice can happen quickly and without notice, is a dangerous condition, and should be avoided--even if you have a plane equipped for flight into icing conditions. When you flight plan, be sure to heed pireps (pilot reports) about any ice experienced. If mild rime is encountered, and you have a plane certified for 'known ice,' you may be able to avoid it, or may not even get into it. But if the airliners are consistently reporting icing, best to use a different route or postpone the flight. Remember, it's illegal to fly into 'known ice' conditions if your plane is not certified for 'known ice.'
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DJSchaut
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DJSchaut
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