Precipitation
Surrounded by the world’s largest temperate rainforest, Hoonah’s climate is defined by abundant rainfall. Early fall tends to be the wettest part of the year, with October receiving nearly 10 inches of rain, while late spring and early summer is the driest. While drought is uncommon due to this high rainfall, Southeast Alaska experienced its first ever extreme drought from 2016-19, which threatened salmon populations, increased insect abundance, and limited power supplies from the hydro plant. Hoonah has already experienced an increase in rain relative to the 1990s. Many tribal elders have shared stories of decreased snowpack within their lifetimes, recalling when the snow would routinely reach to the roofs of their houses, and it used to stay on the mountains well into the summer.
THE AVERAGE RAINFALL IS EXPECTED TO INCREASE BY 3-18 PERCENT BY THE END OF THE CENTURY. [1]
As overall precipitation is predicted to increase across Southeast Alaska, the risk of drought is expected to decline. While there are uncertainties in the model, a drought of magnitude experienced in 2018-2020 is about half as likely to occur by 2050. The figure below shows how rain is likely to change under a medium emissions pathway. Slight decreases are predicted throughout the summer for the next few decades, followed by an increase at the end of the century. In Juneau, the average annual rainfall has already increased by 20 inches over the last hundred years.
Figure 2 Precipitation forecast for Hoonah under a medium emissions pathway through the end of the century. Figure from the Scenarios Planning for Alaska+Arctic Planning, University of Alaska Fairbanks.
BUT THE TOTAL SNOWFALL MAY DECREASE BY UP TO 60 PERCENT.
Up to 80 percent of the area that now gets snow may not do so by the end of the century. Decreased snowpack will have a variety of effects on the ecosystem, including increased salmon mortalities due to higher water temperatures and lower rivers, a decline in yellow cedar due to a lack of insulation on the roots systems and risks to the municipal water supply and energy production. [2]
PRECIPITATION PATTERNS ARE GOING TO SHIFT, WITH INCREASED PERIODS OF BOTH DROUGHT AND HEAVY RAINFALL.[3] [4]
Severe weather events, such as atmospheric rivers, are expected to increase by two- or three-fold by the end of the century because warmer air can hold more water. While too little rain causes the water in rivers to get too warm for salmon, too much can push the eggs out of the gravel before they have a chance to hatch. Heavy rains also increase the risk of landslides, which can both directly harm residents and reduce road access for subsistence activities. While overall rainfall is going to increase, it will become more variable and leave periods of drought.
What does this means on the ground?
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My above comments are mainly asking for this to be much more personalized, and any steps you can take throughout the document to give it a more personalized form will greatly increase this document’s usability, and can also make good talking points.
You may be able to work on this during the trip.