It has been a curious - and frustrating - spring! We just experienced the third coldest April on record (since
1904) with average monthly temperatures about 15 degrees (F) below normal.
Additionally, it was the tenth snowiest April on record. As you can see
from the photos I am including, we still have a considerable amount of snow
on the ground. I measured the snowpack at 320 mm, which was averaged over 5
different measurements. Interestingly, the range of measurements was from
300 mm to 360 mm: there is a lot of variation in snow depth. I believe that
is due to the several different periods of partial thawing that we have
seen since mid-March. The snow has melted a lot more in some areas than
others, perhaps due to the angle of sunlight, shade vs sun, etc.
Additionally, there was about 5 mm of fresh snow (!) on top of the
snowpack. (You probably cannot see, but it was lightly snowing when I took
the photos of my SIMB plot). The temperature at the time, 11 am, was 5.5 C.
Funny that it should still be snowing above freezing - it must be colder
aloft than on the ground.
Since 2009, when I first started collecting SIMB data, we have not had any
snow on the ground on 3 May.
This is the time of year when we normally see budburst and the begining of
green up. I assume it will be delayed this year. I looked at budburst data
for the LTER (Long Term Ecological Research) site at Bonanza Creek, about
25 km NW from our house. This is an area of boreal forest that has been
studied by UAF scientists for many years and they have been tracking many
forest parameters, including budburst of white birch (Betula neoalaskana),
since 1976. Their records show that over the last 30 years, the date of
budburst has averaged as 11 May. However, the range of dates is from 1 May
to 26 May, so there is a lot of variability. I wonder when it will happen
this year?
(My understanding of what triggers budburst, is moisture available to the
plant/ tree and the air temperature. One of the best gauges of the timing
of budburst is the number of freezing degree days; that is the accumulation
of dates when the air temperature rises over freezing, also called the
Growing Degree Summation. There is a really good GLOBE activity for
calculating this starting on page 9 of the Budburst Protocol.)
Of course, our late spring has big implications for when I can start my
garden. Every April 1st I spread
wood ashes that we accumulate during the winter (from our wood furnace) on
the garden beds. This darkens the normally white snow and causes an albedo
effect: the darker areas absorb more heat energy and melt the snow more
quickly. (The ashes also add valuable nutrients to the soil.) It is curious
to note that the beds are so bare of snow and yet the paths
between the beds, where I did not put ashes and which are at ground height,
45 cm lower than the beds, have mounds of snow that are so much deeper: you
can see how much difference albedo makes! I
did not mention how much daylight we are experiencing now. I believe this
is an important fact to include since our days are so long now (over 17
hours of daylight) and yet the weather is so winter-like. It is very, very
strange for us to see snow falling after 10:00 pm - in daylight!! You would
think that with all the daylight we would have warmer temperatures.
Yesterday, 3 May, the sun rose in Ester, AK at 5:12 am and set at 10:26 pm
for a total length of daylight as 17 hours 14 minutes.
Thank you for taking the time to read this really long-winded report! But I
did want to share with you the unusual spring that we are experiencing. I
could also mention that I have not seen or heard any migrant songbirds yet
this year, although I know some have been sighted in interior Alaska. I
feel sorry for them since they have such a short time to breed and raise
young - this year will be even harder for them.
