2019 - Robert's botanical adventures in Northern California

[Hoy]

Robert,

your natural meadows look similar to ours but the details are different! Wet meadows are common here on sloping terrain and the vegetation depends much on the underlying bedrock. Usually it is acidic granite or gneiss and the vegetation is poor (few species).

We still have a rather dry weather here at the west coast. They get the precipitation at the east side of the mountains. And at this time of the year that means they get snow except at the outer coastline. The temperature is about normal for the season, which means it is lower than last year. October was the coldest October in 10 years for the country. (We had slightly above normal here.)

Although we had a very cold spell about two weeks ago some plants are still in flower, like this rose.

[Robert]

Hi Trond,

We are preparing for yet another north wind event with the accompanying power outages (preventive to avoid downed power lines from igniting wildfires). Some moisture is preceding this event. If we are lucky we might squeeze some rain and/or snow out of this system over the Sierra Nevada before the strong, dry, north winds arrive.

Sadly the overall general dynamics of our weather have not shifted much. There are some transient short-term changes, however the dominant pattern conducive to above seasonal average temperatures and below average precipitation appears as if it will continue for the next 30 days. As an example, yesterday’s high temperature at the farm was 77 F (25 C), a new record for the date. The old record was 76 (24.4 C), set in both 2005 and 2008.

As time permits I will expand upon the topic of seasonal seeps and wetlands in our portion of the Sierra Nevada Mountains (the dry looking photograph from my previous posting).

[Robert]

Hi Trond,

Jasmin and I enjoyed your photograph greatly! 



The nose of the East Asian jet has broken through to the west coast of North America. This is good news, as the short-term forecast for a major shift in our weather pattern is very likely to pan out accurately. The first significant, and much needed, valley rainfall and mountain snow is scheduled to arrive in the coming week and linger for a period of time. Snow levels are forecasted to be quite low. A week from now I hope to be tallying snow accumulations in the Sierra Nevada Mountains and the upper foothill region. As I tally the totals, I will keep you posted as to how they measure up to the seasonal averages.

In the 8 to 14 day time range, it appears that we will be returning to a dry weather pattern. Temperatures are likely to be average to slightly above the seasonal average for this time period. During the 15 to 30 day period, and beyond, the dynamics do not look encouraging. Above seasonal average temperatures and below average precipitation look to dominate this time frame. This does not mean that there will be no precipitation or cold weather, just a general trend with temperatures and precipitation. At this time, it appears that we will be looking to the January through April precipitation season to pull us out of a precipitation deficit, maybe the “March Miracle” as it has been referred to in our area.

Now that it appears that we are at the cusp of the snow season in the Sierra Nevada Mountains, I will be shifting to my winter activities in the mountains. The site in the above photograph is likely to be inaccessible until next spring, however there is always a great deal for me to do in the mountains. Wintertime reports are fun and can be enlightening.

[Hoy]

Glad you enjoyed the photograph Robert!

We are enjoying the rose! Every day. It is just outside the window of the sitting room . I am looking at it when I write this. I am also looking at your photographs. Hope you will get a large amount of snow! I wonder, is it no option for you to use snow shoes or skis in winter?

We have mild weather now. Not uncommon though although we have had 10C during daytime here at the coast. What is more uncommon in November is lack of precipitation at the west coast and more than normal in the east. This pattern seems to continue next week and beyond. (The weather systems bringing rain are coming up from south and passing at the east side of the mountains in stead of the more normal pattern: entering from south west and hitting the west coast.)

The foxglove (Digitalis purpurea) waiting for spring! it is native and very common here.

[Robert]

Trond,

The current weather pattern is extremely interesting. How often does this occur in Norway?

As for my high elevation data loggers, etc...

Yes, I can snowshoe or use cross country skis the reach some of the sites. A few sites are extremely remote and would require an overnight stay in the snow country to reach them once the snow season arrives in the Sierra Nevada Mountains.

[Hoy]

Trond,

The current weather pattern is extremely interesting. How often does this occur in Norway?

I have no data on how often this weather pattern happens but it is not very often! The met says that Bergen (the major city at the west coast) hasn't had so little rain in fall since 1891. It is 1/3 of normal. Oslo has 2x normal. Another factor is wind. We have not had fall storms. They are south in France and Italy! Usually we have several during Nov.-Dec.


As for my high elevation data loggers, etc...

Yes, I can snowshoe or use cross country skis the reach some of the sites. A few sites are extremely remote and would require an overnight stay in the snow country to reach them once the snow season arrives in the Sierra Nevada Mountains.

An overnight stay in the snow would be nice, wouldn't it I did it a lot when I was young.....

A creek close by. Although less rain than normal it is no lack of water!

[Hoy]

November is the driest November ever (as long as the precipitation has been measured which is 119 years) here at the west coast.

[Robert]

A most welcome change in the weather occurred this week. After weeks of dry weather with near record breaking warm temperatures, the pendulum swung and now we are experiencing near record breaking cold temperatures and mountain snow. The snow levels have been quite low, with snow levels down to 2,000 feet (610 meters).



The arrival of the snow season is very late this year, however it was not the latest arrival date.



Now it appears that we are in for a period of unsettled weather. The 7-day GFS forecast advertises a series of storms arriving over the next week. With a split jet stream, subtropical moisture is likely going to be drawn into next weather systems. Snow levels will be much higher, yet precipitations amounts are likely to be much greater.

The last storm produced average precipitation amounts at our Sacramento home and the El Dorado County farm. At the farm precipitation amounts for the season, to date, are only 47% of the 37-year average. In the Sierra Nevada, orographic lift produced some good snow accumulations. At one of my high elevation monitoring sites there was approximately 36 inches (91 cm) of snow, with a water content of 3.57 inches (91 mm). This is 112% of the 15-year average to date. This is certainly a good start to the snow season, despite getting off to a late start this year.



Looking into the crystal ball, the 7-day GFS forecast seems very reasonable. In the 8 to 14 day time frame, precipitation is likely to wind down as a drier weather pattern develops. Temperatures are likely to be average to above average, with below average precipitation. It is likely there will be another outbreak of arctic air, at some point, as the northern split of the jet stream continues to be shunted to the north and is then driven southward into the U.S.A. Initially, I expect the trajectory to be farther to the east, creating a drier weather event for us in California. If this pattern continues, the arctic air is likely to arrive farther to the west with each occurrence.

It is extremely difficult arriving at a somewhat accurate 8 to 14 day forecast. Day 15 to 30 is even chancier, however I will continue to take a swing at this (This is a great learning tool for me, even if I am incorrect with my original assessment). At this time, it appears that the general blocking pattern will persist. Below average precipitation and above average temperatures seem most likely. With a split in the jet stream, out breaks of arctic air and advection of subtropical moisture are still possibilities.

Stay tuned and we will see what happens.

[Hoy]

Robert, it looks good with snow!

Here also the weather pattern has changed the last two days. We got 2mm of snow yesterday evening but it rained away during the night. The dry period has ended and we are in for a lot of rain this week. Today it is 3C here but during the week we will have 8-10C. Most of the country has snow now except the outer coast.

[Robert]

Over the past week I have been analyzing meteorological data from a high elevation site in the Sierra Nevada Mountains, 6,700 feet (2,042 meters) where I conduct my research. The above graph illustrates the monthly water content of the snow distributed over the precipitation season, July through June. Very typical for our region, snow pack and water content peak in April. The seasonal distribution and water content of the snow pack has a major impact on the hydrology of the Sierra Nevada Mountains and plant ecology.



The number of days with snow cover, each season, impacts both water hydrology and plant ecology/physiology. Over the 12-year period, 2007-2008 through 2018-2019, the number of snow cover days declined by 1.5%. This is a significant percentage; however there can be a large variance in snow cover days season-to-season. With time I will include additional data back to 1972. This will provide a much more accurate and meaningful representation of this data set.



The above chart depicts the change in the average annual temperature over the 13-year period, 2006-2007 through 2018-2019. The 1.2 F (0.67 C) rise in the average annual temperature over this time period is alarming and may represent acceleration in the rate of climate change in our region.



This chart compares the change in the average annual temperature at our Placerville farm and the above referenced study site over the same 13-year period. The Placerville farm site is at 1,460 feet (445 meters) elevation and within 50 miles (80 km) of the study site. The Placerville site is an excellent proxy for the comparison of the rate of temperature change at the study site. The Placerville data, dating back to 1982, also helps put the temperature trends into a longer-term perspective.

Subtle changes in temperature and water availability can impact plants and plant communities. For example, above 77 F (25 C) the solubility of CO₂ in plant tissues decreases more rapidly than that of O₂. This begins to change the more typical 4:1 carboxylase:oxygenase ratio found at the rubisco site (in most temperate plants). The carboxylase:oxygenase ratio can drop as low as 2:1, severally impacting carbon fixation and plant growth. In addition, with dry soil conditions the closure of stomata to limit water loss can further increase the rate of oxygenase at the rubisco site. Of course, temperature and the availability of water (too much or too little) can impact plants and plant communities in many other ways.

Human activity is having a profound impact on plants and plant communities in our region. In our region, healthy unmanaged ecosystems are clearly much more resilient to the stresses occurring in our area. There are limits and thresholds. If crossed, change could accelerate and create unforeseen undesirable consequences very quickly and reduce the ability of modern human society to adjust to the changes in our environment. It is because of these circumstances, I feel an urgency to proceed persistently with my work.

[Hoy]

Your findings are consistent with these graphs show. The temperature has increased more in Svalbard than any other place I have heard of. Also Oslo has had a significant temperature increase since 1970.

[Robert]

Hi Trond,

Thank you for sharing the graphic, it was very interesting. The rising temperatures recorded in Norway are very similar to those recorded in Alaska and other arctic regions. Due to the rising temperatures, profound ecological changes are taking place in Alaska. Do you see and/or hear about similar changes in Norway?

I am frequently asked two questions concerning climate change in the Sierra Nevada Mountains: 1.) Are temperatures increasing in the highest regions of the Sierra Nevada Mountains at the same rate as those recorded in the arctic? 2.) Are the Sierra Nevada Mountains becoming drier? I am still working on the answer to the first question, but at this time the answer appears to be no. As for the second question, over the last 150 years there is little evidence of any major shift in the average annual precipitation (at least in our area- the Crystal Range). However, this does not mean that the Sierra Nevada Mountains are not becoming drier. There have been plenty of droughts and extremely wet phases. A great deal of investigation is still required, but progress is being made using multiple methodologies.



The above graphic is of the average annual temperature, based on the complete data set, 1987-1988 through 2018-2019, at the Placerville farm. The last few years have been relatively cool, but nothing in relationship to those seen in previous years. The next few years need to be watched closely. There are many factors that could easily lead to new high temperature extremes in the coming years.



I spent a good portion of the day in the Sierra Nevada Mountains. The misty clouds in the American River canyon were beautiful to watch.



Most of the snow that fell earlier in the week, about 40 cm, had melted. I recorded 9.5 cm at this site, 5,125 feet (1,562 meters).



Despite the cloudy conditions, I avoided most of the heavier rainfall. Temperatures were in the low 40’s F (plus or minus 6 C) most of the day.



Arctostaphylos mewukka ssp. mewukka is one of three Arctostaphylos species found at this site. Considerable phenotypical variance is seen among the plants. Hybrids between the other two species, Arctostaphylos patula and A. viscida ssp. viscida, are a possibility.

[Robert]

Arctostaphylos patula is quite common at this site.



Aspidotis densa is a very tough little fern. Senescence is slow to set in this season.



This seasonal wet spot is extremely interesting. I closely monitor this site and have logged a few rare plant species that grow annually in this unique habitat. A large brush-clearing machine with caterpillar treads passed within a few centimeters of this site. A direct hit would have severely damaged this fragile ecosystem.



Later in the day I moved down the mountain, a bit, to check another site. At this elevation, 4,000 feet (1,219 meters), one starts to encounter Buckbrush, Ceanothus cuneatus var. cuneatus.



My primary purpose for stopping at this site was to check on a stand of Johnsongrass, Sorghum halepense. I am quite concerned that this C4 grass species is becoming established at this elevation. If temperatures continue to increase in the coming years it is very possible that this C4 grass, and other invasive C4 species, could obtain, in some cases, a competitive advantage over the native annual and perennial C3 species in this area. In addition, the plants are highly resistant to herbicides. They have been sprayed repeatedly and have not only persisted, but appear to be thriving. There is also the possibility that this species will never become an invasive pest, but it is a strong indicator of the climatic shifts that are taking place. It also joins a long list of other noxious, invasive species that have invaded the Sierra Nevada Mountains.

[Hoy]

Hi Trond,

Thank you for sharing the graphic, it was very interesting. The rising temperatures recorded in Norway are very similar to those recorded in Alaska and other arctic regions. Due to the rising temperatures, profound ecological changes are taking place in Alaska. Do you see and/or hear about similar changes in Norway?

Robert, it is written a lot about the changes following the rising temperature. The soil is thawing (less permafrost) and this lead to landslides and methane release in summer. In winter periods of mild weather and rain instead of snow changes the snow cover to solid ice. Animals like the Svalbard reindeer suffer as they usually easily dig through the snow to reach the plants they eat in winter. The sea ice decrease and now the west coast of Svalbard is free of ice  most winters.

On the mainland warmer temperatures lead to the tree line steadily creeping higher. Combined with less grazing (less livestock) the tree line will at least go 150 - 200m higher vertically in a few years. This easily seen. I encounter small birches where I never saw any before. And pine and spruce follow.



Nice to see some of the beautiful Arctostaphylos shrubs again!

I didn't know the Johnson grass. Had to read about it. Seems to be a nasty weed in more than one sense.

[Robert]

Hi Trond,

Thank you again for all the information. I just saw a report on TV (while visiting my mother) that Victoria Falls had dried up due to a persistent drought in the region. The reporter stated that scientist believe this may be due to global climate change. Basically all atmospheric scientists understand that anthropogenic global climate change is a reality. I monitor OLR daily (outgoing long-wave radiation). The western Indian Ocean has been very active since ~ October of 2019. A persistent pattern of upper level convergence has been in the vicinity of the Maritime Continent since ~ July/September 2019. Even the MJO has been inactive or has been tending to retrograde in the vicinity of the Indian Ocean. I would strongly speculate that this persistent pattern might be related to the drought in Africa. I do not know, but it sure seems suspicious.

It was been pouring rain here in our part of California. As of yesterday, we had average precipitation to date. After today, we are certainly above average. The stormy weather gave me a chance to work on my dynamic weather model. I ran the model with known starting points and known outcomes, 2000 through 2011. The model preformed well with temperatures, 78% accuracy; with precipitation not so well, 56% accuracy. Concerning the precipitation, well, I could flip a coin and most likely get the same percentage, however there are three potential outcomes, above, below, and average, so I guess I did a little better than flipping a coin. As you can imagine, to get any sort of dynamic model to work on a laptop I am doing mega parameterization. It is kind of amazing that it works at all. Even this extremely simple model is more complex than one might think. I spent all day working on equations for just one small portion of the model. Since there are other things to do, it will be months (most likely a year or more) before I can test the new version completely. Working on this model is good practice for the plant/ecosystem model I will be creating for my study area of the Sierra Nevada Mountains. I always liked Jack LaLanne’s saying, “use it or lose it”, so I put this saying to practice.