With bluebonnet season just a few weeks away, the time has come to look at the available weather data in order to try and forecast what the 2022 season might be like. This annual series of articles began in 2020 as a way to learn more about how to more accurately predict where bluebonnets will be blooming through analysis of weather data prior to the season, and then to chronicle what I had personally seen during the bluebonnet season by reviewing my findings on the ground after the season is over. Predictions and reviews from previous years can be found here.
Though there are many contributing factors for a bluebonnet bloom, the most important by far is rainfall, on which the first three articles of this four-part series will focus. We begin, as usual, with the rainfall data from the Big Bend in West Texas, since these are the first bluebonnets to bloom in the state. Below, rainfall maps showing the departure from normal rainfall are presented for each month from September 2021 to January 2022.
Because the purpose of this series of articles is only to attempt to identify the locations that are most likely to have bluebonnets, rainfall is the only bloom factor that is examined. I have chosen to omit the data from February because it is not available at the time of this writing, and also because I believe it is the least important month in terms of affecting a bluebonnet bloom, even though in all likelihood it does have some bearing on the bluebonnets' development.
Seed germination period
Rainfall during what I term the seed germination period is more crucial for bluebonnet development than rainfall during any other period. The germination period runs from sometime in September to sometime in November. This doesn't mean that bluebonnet seeds can't germinate during other months of the year, just that this is when the large majority of them will germinate, if they are going to do so.
Less rain fell during the tail end of the monsoon season in September 2021 than fell in September 2020. A few small areas northwest and west of the Chisos Mountains as well as the area just west of the Dead Horse Mountains (Sierra del Caballo Muerto) and the area around Rio Grande Village saw average rainfall, while the remainder of Big Bend National Park received anywhere from a half inch to two inches below the average. Areas west of the national park, including the eastern half of Big Bend Ranch State Park also received one to two inches below the average. Based on the average rainfall totals cited in the caption above, the dark yellow color likely indicates that no rain whatsoever fell in those areas.
Rainfall across the Big Bend was generally down again in October 2021, ranging in most places from a half an inch to two inches below average. Again, the dark yellow color likely indicates that no rain fell in those areas. The bright spot this month was up on the Mesa de Anguila, between Santa Elena Canyon and Lajitas, which saw in some areas up to three inches above the average, as did the last couple of miles of Terlingua Creek before it empties into the Rio Grande. A small area west of Lajitas also received between a half an inch and two inches above average, and the area around Rio Grande Village received about average rainfall.
In November 2021, rainfall across the western half of Big Bend National Park as well as the eastern half of Big Bend Ranch State Park was about average, while the eastern half of the National Park ranged between average to an inch below average. The light yellow color on the right side of the map likely indicates that no rain fell in those areas.
Rosette development period
The rosette development period runs from sometime in November to sometime in February. This is the period when bluebonnet rosettes are going through a process known as vernalization and developing their root structure. While rainfall is still important during this time, it is not as important as it is during the seed germination period.
Most of the Big Bend region received average rainfall in December 2021, with some exceptions in and around the Chisos Mountains and in an area west of the Dead Horse Mountains in the northern portion of Big Bend National Park.
During January 2022 the entire Big Bend region saw average rainfall.
2022 Big Bend bluebonnet forecast
Predicting a bluebonnet season is difficult to do with accuracy due to the fact that there are so many different factors are involved in a bloom that are impossible to evaluate. Each wildflower season is unique and presents different opportunities
After little to no rainfall throughout a large portion of Big Bend National Park during September and October of 2021, I do not expect there to be very many bluebonnets in general. Of course, there should be the usual roadside bluebonnets along the paved roads, which get the benefit of runoff from the nearby asphalt with every rain, but one shouldn't expect there to be a whole lot more than that. The one region of interest that I think could be the exception to this is the Mesa de Anguila and the last couple of miles of Terlingua Creek before it empties into the Rio Grande. With the above average rainfall the area received in October (which may be the most important month of all for bluebonnet seed germination) and the average rainfall in the following three months, it is probably the best area in the entire region to explore if you are interested in seeing bluebonnets. Having never hiked that area myself, I cannot say if bluebonnets are wont to grow there or not, even during the best of bluebonnet seasons. As always in the Big Bend, if you choose to hike there be aware of your own physical limitations and always carry plenty of water.
Castolon Cooperative Precipitation Data. (n.d.). Retrieved February 03, 2022, from https://www.weather.gov/maf/cl...
Lajitas Cooperative Precipitation. (n.d.). Retrieved February 03, 2022, from https://www.weather.gov/maf/cl...
Merlo, J. (2020, January 11). Contributing factors for a bluebonnet bloom (Part I). Retrieved from https://www.jasonmerlo.com/gallery/contributing-factors-bluebonnet-bloom-texas/
Merlo, J. (2020, January 12). Contributing factors for a bluebonnet bloom (Part II): The Big Bend of Texas. Retrieved from https://www.jasonmerlo.com/gallery/contributing-factors-bluebonnet-bloom-big-bend-texas/
NOAA. (n.d.). Advanced Hydrologic Prediction Service. Retrieved from https://water.weather.gov/precip/#
Panther Junction Cooperative Precipitation Data. (n.d.). Retrieved February 03, 2022, from https://www.weather.gov/maf/cl...
Rio Grande Village Cooperative Precipitation Data. (n.d.). Retrieved February 03, 2022, from https://www.weather.gov/maf/cl...
Vernalization. (2019, December 17). Retrieved from https://en.wikipedia.org/wiki/Vernalization