This Memorial Day weekend, a rather unusual meteorological phenomenon snuck up on unsuspecting Sierra-bound travelers. Several mountain roads had to be closed as certain segments were covered with no less than four inches of snow.

The routes which were considered to be unfit for traffic included the Tioga Pass Road in Yosemite National Park, which was opened for the season only three days ago. Also due to icy conditions, Glacier Point Road was closed yesterday.

This came as a surprise for many, as last weekend’s temperatures were actually around 20 degrees above normal. In just one week, temperatures dropped more than 10 degrees below what is considered as normal for this time of the year and, according to forecasters, the situation is not going to change, at least for a few days.

Sequoia and Kings Canyon National Parks also got some snow this week, but access roads to these areas were reopened on Saturday. According to Sequoia National Park spokeswoman Alexandra Picavet, the snow didn’t seem to discourage visitors, as more than 1,400 of them entered the park's gates by Saturday afternoon.

One of the reasons for the great show-up may be the fact that most visitors to Yosemite Valley for instance (but that probably goes for any park), don’t venture more than a quarter of a mile from their cars, so a bit of snow doesn’t seem to be much of an impediment for a ten-minute hike.