The average annual temperature in 2010 for Fairbanks was 28.9°F, a positive departure of 2.0°F from the normal. The mean annual precipitation was 10.31, very close to normal of 10.34. Snowfall, however, was below normal, recording only 28.8 in the calendar year. This is 39.2 below average for Fairbanks.
2010 started out on the cold side with January registering -13.7°F, 4.0 °F below the long-term monthly average. On 12 January, a minimum temperature of -41°F occurred, the coldest temperature of the year, and only matched once more during the year on 15 December. Precipitation was recorded on only 22nd with a water-equivalent value of 0.02; this was the second lowest January snowfall on record.
In February, temperatures averaged 2.9°F, 6.7°F above the long term mean. A strong Chinook, advecting warm air across the Alaska Range from the South, warmed the temperature to a pleasant 37°F on the 19th, a near record high temperature for this day. However, these high temperatures and some light freezing rain made the road conditions difficult to drive. Precipitation for the month was 0.15 water-equivalent, 58% below normal and only 13 of snow were measured on the ground by the end of the month. Missing the insulation properties of the snow cover, freeze-up problems with water and sewer lines were experienced.
The average temperatures in March was 10.8°F, just 1.3°F below normal. The coldest day occurred on the 13th with a chilly -26°F, while the maximum of 48°F was measured towards the end of the month (28th). Precipitation continued to be light with only 1/3 of the expected amount occurring. This continued deficit in snowfall made the winter of 2009/10 the third lowest total winter in terms of total snowfall accumulated through the end of March since 1930, the period for which we have records. The snow pack on the ground measured only 10 at the end of March.
Frequent southerly flow aloft brought above normal temperatures in April and hastened the snowmelt, which occurred a full week earlier than usual. Only traces of snow fell throughout the month, and the seasonal snow pack went from 10 on the 1st to less than 1 on the 15th. Precipitation occurred as rain by the end of April and some flooding occurred on the Salcha Slough, southeast of Fairbanks and on the Chatanika River north of Fairbanks during the third and fourth weeks of April, when afternoon temperatures rose above 60°F. The maximum for the month was measured on the 28th at 68°F, the monthly mean temperature was 39.4°F, 6.8°F above normal, and on the 19th the old daily maximum of 66°F was matched.
The temperatures in May continued to rise, especially during the second part of the month, when the temperatures were far above normal. The mean monthly temperature was 54.0°F, 5.2° above normal, making this the third warmest May on record. The high temperature of the month occurred on the 27th with 82°F; it is a rare occurrence that temperatures over 80°F are recorded during May. On the 6th the minimum temperature dropped to 29°F, a day after a small storm front blew through the area and dropped a trace of snow. This had several interesting effects. First was the timing of green up around Fairbanks. Green up is the first appearance of the green forest canopy of deciduous trees. This year green up in Fairbanks occurred on May 6th - about 2 days earlier than usual. The second was the remarkably large pollen release. In Fairbanks, the peak concentration of birch pollen was 2,019 grains per cubic meter, measured on the 10th. Such high concentrations of pollen can cause respiratory stress to people with allergies. Precipitation measured 0.24, which is 40% below normal for the month. Low precipitation combined with the above normal temperatures conditions favored the expansion of wildfires. On the 16th a holdover wildfire from 2009, the Minto Flats fire, sprang up and had covered 15,000 acres by the 20th. Wildfire conditions became more serious during the closing days of May. Temperatures reached the 70's and lower 80's and extensive areas of smoke spread over the Interior. An air quality advisory was issued in Fairbanks on the 29th.
The average temperature in June was 59.8°F, which is close to the normal of 60.3°F. The high temperature of the month was 79°F on the 2nd, lower than the maximum temperature in May. The low occurred on the 14th with 46°F, and it can be stated that the temperatures experienced throughout the month were close to the normal values, as was the precipitation with a monthly total of 1.35. Wildfires were especially active for the first and last weeks of the month, while cooler, sometimes rainy weather during mid-month restrained the growth of the fires. Still, the total area burned increased from roughly 260,000 acres on the first to about 450,000 at month's end. Extensive smoke was intermittently observed over large areas of interior Alaska.
Temperatures were close to normal during July with a mean value of 62.6°F, only slightly below the mean of 63.0°F. The high temperature was 85°F on the 9th, and the low was 47°F on the 28th. Precipitation was high with a monthly total of 3.11, which is 76% greater than normal for the month. The highest one-day total was 1.35 and occurred on the 21st, and new record for that day. Between 3 and 4 pm, 1.15 fell in just one hour setting a new hourly record rainfall for Fairbanks. From the 10th to the 31st, Fairbanks recorded rainfall on all but four days, which is unusual for this time of year. Due to the abundant rainfall wildfires slowed down considerably. Nevertheless, smoke from nearby fires drifted over Fairbanks during the second week of July, prompting air quality advisories to be issued.
August began with very warm weather and temperatures that were noticeably above normal, reaching into the low 80's during the first 4 days of the month. Further, on the 15th, a new record high of 91°F was observed for this day, surpassing the old high of 86°F set in 1926. (The 1920's were a very warm decade in Fairbanks, and 1926 recorded the highest annual temperature ever measured in Fairbanks in over a century of data.) Furthermore, it represents the highest temperature ever recorded in Fairbanks so late in the season. Altogether, August was 3.1°F warmer than normal with a mean temperature of 59.9°F, while the precipitation was recorded at 1.46, which is 84% of normal for this month. The combination of above normal temperatures and below normal rainfall rejuvenated many wildfires, but rainfall calmed this for about a week. On the evening of the 15th, the large flames of the Willow Creek fire were clearly visible in Fairbanks, 15 miles away and air quality advisories were issued in Fairbanks on the 5th and on the 19th as forest fire smoke drifted towards Fairbanks. As of the end of August, wildfires had burned 1.l million acres in Alaska, which is close to normal. On average over the last decade, 853,000 acres burn annually, about 90% of these in Interior Alaska.
The average temperature in September was 47.1°F, 2.3° warmer than the long term mean. The high temperature for the month was 70°F on the 13th, and the minimum was 14°F on the 28th. The first frost of the season, at 32°F, occurred on the 22nd, and the daily minimum temperature stayed below freezing point for the rest of the month. The late frost extended the normal length of the growing season by 2 weeks, which can be very important for gardeners and agriculture. Total precipitation for the month was 1.19, 12% above the normal amount. On the 8th, a record rainfall of 0.78 occurred, breaking the old record of 0.59 set in 1920. There were reports of very light snow flurries on the 26th, in the hills north of Fairbanks, specifically in the Murphy Dome area.
The onset of winter was mild and gradual, as the first part of October was dominated by a low-pressure system affecting the Fairbanks area, bringing warmer minimum temperatures until the 14th, when a significant drop in nighttime temperatures occurred. The mean monthly temperature was 27.5°F, 4.0° above the long term mean. The high temperature was 59°F on the 1st and the 2nd, and the low occurred on the last day of the month with a chilly -4°F. Precipitation was measured at 0.45, about ½ of normal. On the 10th the first measurable snowfall of 0.8 occurred, while the monthly total amounted to 7.7. Only 9 cloudy days were observed for the month, but on 15 days some morning fog occurred. Many local rivers had very little ice by the end of the month, making travel on the rivers unsafe.
November continued and surpassed the above normal temperatures observed for Fairbanks since August. The mean monthly temperature was 11.9°F, an impressive 9.6°F above the long term mean. The high temperature for the month was 37.0°F observed on the 3rd, and the low was -32°F observed on the 30th. Monthly precipitation was recorded as 1.71, 1.03 above normal for the month. However, the most dramatic event Fairbanks experienced was a rare freezing rain event between the 22nd and 24th of November, when 0.95 of rain fell. This is the second greatest winter rainfall on record for Fairbanks; the all time high record of 0.99 occurred on January 20th 1937. This event did, however, break the record for the longest duration of continuous winter rainfall, as rain fell for 39 hours, far surpassing the old record of 23 hours set back on 6-7 March 1921. Roads were icy and treacherous for several days and there were numerous accidents. Schools were closed from Monday November 22nd through the Thanksgiving weekend. Most outdoor sporting events were canceled because of the ice. Many flights were canceled at the airport. There were a number of power outages, but due to the mild temperatures, none resulted in significant damage. Foresters said that large stands of birch trees were badly injured by a half-inch accumulation of ice that weighted down and snapped branches. The total amount of rain in the Interior during this extraordinary event ranged from 0.63 at Eielson Air Force Base near Fairbanks to 2.10 at McGrath, in the southwest Interior. The local media dubbed this storm the 'Icepocalypse of 2010'.
December ended the 4 months span of above normal temperatures. Indeed, Fairbanks was much colder and drier than expected. The mean monthly temperature was a chilly -17.9°F, a substantial deviation of -12.0°F from normal. During the middle of the month, ice fog was observed for several days, and on the 15th, -41°F was recorded, matching the old record low for this year also observed on 12 January 2010. Ice fog formed for several days, making driving conditions difficult due to poor visibility. The twenty-five observed consecutive days of subzero temperatures did constitute a long period of colder than normal weather, including 4 days during which the thermometers reached -40°F. During much of the cold spell in December temperatures in the hills were significantly warmer than down on valley floor, the well-known fact of the semi-permanent surface inversion, which is common in Polar Regions in winter. This shallow layer of cold air effectively trapped pollutants and on December 1st, the concentration of particulates in Fairbanks rose to 56.4 micrograms per cubic meter of air, prompting several air quality advisories throughout the month. During the last week of the month, a steady warming trend was observed, and finally on the 31st a temperature of 19°F occurred, the maximum for the month. Snowfall was light during the month with about 1/3 of the expected value.