This past winter was the snowiest on record in the Northern Hemisphere, with accurate data going back to the winter of 1966-1967. Although that specific snow data only goes through March, the western one-third of the United States continues to build their snow pack. Several storms in the past few weeks have dropped significant snows in the higher elevations of the Rocky Mountains.
It was cold enough that on May 24, even the lower elevations around Salt Lake City reported measurable snow, which was the latest such event for the city since records began. Currently, the snow pack over the Rocky Mountains is listed as 137% of normal, with all the major mountain ranges reporting an above average snow pack.
Although the cool wet spring in the Rockies may be bringing some complaints, the snow pack is crucial for summer drinking water and for irrigation purposes and therefore, the melted snow will be very welcomed during the dry summer season.
Here is a graph showing how rapidly Lake Powell has been rising in recent weeks:
On Monday, May 24, the high temperature at Hector Int’l was 90 degrees. That same day the high was 67 degrees in Grand Forks, 68 degrees in Jamestown and only 59 degrees in Devils Lake. A strong warm front surged northward just far enough to bring warm, tropical air to Fargo Moorhead that afternoon.
That 90 degree high was the first time since May 23, 2006 that the temperature locally reached 90 degrees during the month of May. Last year the official high did not reach 90 degrees until June 26 and in 2008 that milestone was not achieved until July 1. Fargo Moorhead does average one 90 degree day during the month of May and as recently as 2004, the temperature reached 90 degrees in April. But since our wet cycle began in 1993, 11 out of those 18 years our first 90 degree day of the year was later than our average date of June 8.
Before the devastating tornado that struck Fargo Moorhead in June, 1957, perhaps the most talked about severe weather event may have been the Empire Builder tornado that hit this area on May 27, 1931. The Great Northern Railway’s transcontinental passenger train The Empire Builder was heading eastbound from Seattle to Chicago. Shortly after leaving the Fargo station, disaster would strike.
Around 4:30 PM, about 8 miles east of Moorhead near Sabin, a tornado, estimated to be a F3 stuck the train broadside leaving only the 136-ton locomotive and 94-ton tender on the track. One of the passenger cars estimated to weigh 70 tons was lifted and moved 80 feet away from the track. Fifty-seven of the 117 passengers on the train were injured by the impact and flying glass. Only one person was killed and witnesses thought his death was attributed to him jumping out a window rather than staying inside the coach.
Yesterday, Tuesday, May 18, the official high temperature at Hector Int’l was 80 degrees which was the first 80 degree or warmer day in Fargo Moorhead this year. The average first day with a high at or above 80 degree is May 5. Our first 50, 60 and 70 degree day this year all occurred remarkably close to the long-term average for such events, therefore this was our first milestone that occurred noticeably later than the average.
Last year our first 80 degree day occurred on April 23 and in 2008 it was on May 16. Since 1881, on only six occasions has the first 80 of the season occurred during June, although, that has not happened since 1983. Since 1881 the average number of days during the year with a high temperature at or above 80 degrees is 61. The cool summer of 2009 brought only 52 such days to this area and the odds favor us experiencing more 80s this year.
When dealing with weather records, it is always important to keep in mind the length of the available data set. Most reliable local weather records have been kept for 130 years or less. There are datasets of a more global reach that have been accurately measured only since the advent of satellite data in the 1960s.
One such record is global snow cover, which was very difficult to determine accurately before satellite technology became available. I mention all of this because this past cold season, from October through March, was the snowiest on record in the Northern Hemisphere, but with the caveat that such data has only been available since the winter of 1966-1967.
Yet, even with such a short data set, it does verify the many stories about last winter’s snowfall, not only in the United States, but in Europe and Asia as well, was indeed more widespread than during any recent winter.
It has become an annual tradition for me to mention in this space when my ornamental crab apple trees bloom. I have come to consider the day my trees bloom as the day that warm weather is generally here to stay. Although a few of the flowers opened up briefly on Mother’s Day, last week’s rain and cold temperatures kept the entire tree from blooming until last Friday, May 14.
This was 10 days earlier than last year when my trees bloomed on May 24 and nearly two weeks earlier than in 2008 when my crabapple trees bloomed on May 27. In the past 10 years my crabapple trees have flowered as early as May 7, 2005 and as late as May 27 in 2008 and 2002.
The recording and study of the timing of natural events, such as when trees bloom, is called Phenology. Such tools use to be one of the natural ways our ancestors used to help determine when to plant each spring.
As we started the month of May, the spring season to that point ranked as the second warmest since 1881 in Fargo Moorhead. But since then, the weather has turned noticeably cooler with temperatures running around 8 degrees below seasonal averages. Even with this significant cool period, through May 11, this spring has only fallen one spot to third place for spring temperatures.
If by chance the second half of May finishing near average (or above), spring 2010 could easily stay in the Top 10 warmest on record. Of course only time will tell, but a significant pattern shift appears to be occurring and warmer weather is expected to move into this area this weekend and current indications are that temperatures should remain mild for at least one week thereafter. If current trends for the rest of the month come reasonably close to reality then our current season could finish as much as 8 degrees warmer than the consistently cool spring seasons of 2008 or 2009.
Our current stretch of cold weather has prompted many people to ask if this is the coldest or one of the coldest starts of May on record. Although the first ten days of May have averaged around 8 degrees below average, it may surprise you to learn that this month only ranks as the 25th coldest of the 130 Mays of record keeping. In other words, although this month has started very chilly, there have been 24 other Mays that have started off even colder.
The average temperature so far this month has been around 45.7 degrees. The coldest first 10 days in May was back in 1907 when the average temperature was 35 degrees and the warmest such period was in 1896 when the average temperature was a summer-like 64.7 degrees.
This month is a good reminder that when you live in the Red River Valley, as a general rule, no matter how cold you think the weather is, the odds are there have been years when it was even colder.
The recent period from March 1 through April 30 was the 2nd warmest such period in Fargo Moorhead since records began in 1881. Although the average temperature through that period was remarkably mild, record breaking warmth was absent. The only warm record broken during that period was on record high minimum recorded on April 14 when the low only dropped to 54 degrees.
It was not extremes in temperatures that made the first two months of spring warm, but rather a consistent period with temperature five to ten degrees above seasonal normals. In 1910, the warmest March and April period on record, numerous records were broken that still stand to this day. The three other Top 5 warmest March and Aprils, 1942, 1946 and 1987 also recorded several record highs that attributed to the warmth of those springs.
So although the warmth during the beginning of spring was certainly not unprecedented, it was achieved in unique circumstances.
May is my favorite month of the year. I enjoy the heat of summer, but each spring I still marvel at the rebirth of the area after the long cold winter. This month can bring consistent days with highs in the 60s and 70s, the flowers start to bloom, plus, when you live in mosquito country, it is often the only warm month of the year where you normally do not have to worry about being bitten.
Sadly, the past ten years has not been kind to those who enjoy May weather. Only three Mays since 2000 have ended with above average temperatures and two of those three finished just slightly above normal. The other six Mays have finished below average, many well below which has been the case so far this month. Plus, the average rain in the 2000s has been 3.3 inches in comparison to the long-term average of 2.6 inches.
Unless this month’s weather changes quickly, 2010 looks to be yet another disappointing May.