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Weather Almanac for August 2006SURVIVING THE DOG DAYS "I've lived in good climate, and it bores the hell out of me. I like weather rather than climate," wrote the great American author John Steinbeck.I really identify with Steinbeck's words. Having grow-up and spent 80% of my life in the Great Lakes region where real changeable weather is the norm, I moved to the good climate of Victoria on Vancouver Island. Its weather bored me. But that has changed. You see, if you noticed a difference in my postings to this website, over the last three months, the reason is that I have been on the move. I left Victoria in late May and have now established my residence about 800 km (500 miles) to the northeast in the small community of Valemount, British Columbia. Valemount sits in the Rocky Mountain Trench. The Rockies form the eastern side of the trench and the multiple ranges of the Columbia/Caribou Mountains form the western side.  Canoe Mountain, Valemount BCSo not only is the weather more variable, spectacular cloud formations play across my skies like a three-ringed circus. I have seen more thunderstorms in the past six weeks than in the past six years in Victoria, and the latest knocked out power for 24 hours. Not quite the wild storms of northern Illinois where I grew up, but fun to watch just the same. And in the short time I have been here, I have also been treated to a pollen storm and a strong whirlwind that marched down the boulevard raising dust and tossing objects as it passed. Yesterday, 30 July, I saw fresh snow on the peaks of those surrounding mountains. As I write, we in North America are firmly entrenched in the Dog Days of Summer. The Summer of 2006 has already been an eventful and record-setting one as it enters its last month. Heat, often setting long-standing maximum records, has reached levels reminiscent of the Hot Summer of 1936 which I wrote about last month. As I write this in late July, the fourth weekend of the month saw at least 63 maximum temperature records set in British Columbia. The records fell from Vancouver Island to Fort St. John. Lytton in the south central region of the province peaked at 42oC (107.6oF) on 23 July. Nearby Lillooet, co-holder of the Province's all-time high temperature fell just shy of 42oC (107.6oF) Even relatively cool Victoria baked in heat reaching the low 30s (mid-80s). For me, I roasted my bones somewhere in the middle. I have no actual reading of outdoor temperature to go by, but I guess the peak was around 36oC (97oF) as it reached 34oC (93oF) in my bedroom. Quite a contrast since four days previous (July 19), the morning low was about 4oC (39oF). Then as the month ended, temperatures fell again to single digits Celsius. Well, that variability is what I have been looking for. As I sat on the deck trying to catch the stray cooling breezes that fell of the mountains, I thought about how British author Jane Austin, in a letter to her Sister Cassandra complained of the heat: "What dreadful hot weather we have! It keeps me in a continual state of inelegance." Across the US, the rest of Canada and much of Europe, heat has been the norm as well. Even Death Valley, California was given a run for its money by the towns in the Dakotas which saw heat surpass 49oC (120oF). I added a few comments to the July Weather Diary on some of those temperatures, but the sheer bulk kept many off that page. Death Valley did make the page as its temperature only fell to a scorching 40oC (104oF) on the 26th. The Dog DaysBut then, what do we expect here across the North American continent? It is after all the Dog Days of Summer. Some claim the period causes dogs to go mad from the heat. Others contend its hot sultry days are "not fit for a dog." Other associations have been droughts, plagues and madness according to the ancients. But in reality, the Dog Days is another of those weather-related terms that really has its origins as much in astronomy as in weather and climate. Like the equinoxes and solstices, it relates to a stellar position, but in this case, it is the bright star Sirius and not the Sun that sets the period. According to the old AMS Glossary of Meteorology (1959), the dog days occur from mid-July to early September in the United States and from the third of July to the eleventh of August in Western Europe. They are typically associated with the hot sultry days of summer. That is their general connection with weather/climate. But as I said, the period has astronomical associations as well. The ancient Greeks and Romans gave Sirius (Latin name from the Greek Seirios, meaning glowing or scorching) the name we now know it by. Alternate names for this star include The Sparkling One and The Scorching One and The Star of Isis. Sirius, found in the constellation Canis Major (the Big Dog and one of Orion's two hunting dogs), is the brightest star (a visual magnitude of -1.46, twice as bright as any other star in our sky excluding the Sun) to those on Earth, and at a distance of 8.7 light years, the fifth-nearest known star. Its light is so bright that the ancient Romans believed that the Earth received significant heat from it, a boost to the solar beam.
Left: The image of Sirius A and Sirius B taken by Hubble Space Telescope A — bigger, B — smaller white dwarf (Credit: NASA). Right: Location of Sirius in Canis MajorThe ancient Egyptians observed that shortly after Sirius returned to view immediately before sunrise (around mid-August in the current calendar; just after the summer solstice then) the annual flooding of the Nile Delta would typically occur. Thus, the star's arrival heralded the rise of the Nile, an alert to those living near its shore. But more importantly it announced the return of fertility to the land, a time to open the irrigation channels and plant the crops. For this reason, those priests charged with calendar-keeping functions kept an eye out for Sirius's return. During this era, the new year began with the return of Sirius after its solar conjunction. To announce the event, a jewel was placed in the forehead of a statue to the goddess Isis in the temple of Isis-Hathor at Denderah. When the light of the star returned to againshine upon the gem, the priest would announce the New Year. In the temple an inscription reads: "Her majesty Isis shines into the temple on New Years Day, and she mingles her light with that of her father Ra on the horizon." What makes Sirius interesting from a meteorological/climatological perspective is that it rises in conjunction or near conjunction with the Sun for over a month (currently from about 3 July to 11 August) and that corresponds to the hottest period of the year in northern Africa and southern Europe. It appears that the Romans were the first to associate the conjunction of Sirius with the Sun with the hottest period of the year and naturally assumed their combined beams caused the heat. They began using the term The Dog Days to describe the peak summer's heat and the period encompassed the 20 days before to 20 days after the conjunction. All were not convinced even then. Around 70 BCE, the astronomer Geminus remarked: "It is generally believed that Sirius produces the heat of the Dog Days, but this is an error, for the star merely marks a season of the year when the Sun's heat is the greatest." If you are extremely displeased with the scorching heat this summer, you can, like the Romans, blame it on the Dog Star, or perhaps you should blame it on global warming. To paraphrase the Bard: "The fault is not in the stars to hold our discomfort but in ourselves." Learn More From These Relevant Books
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