increases in temperature, in one case comparing average monthly temperatures between 25-30°C (77-86°F) with those over 30°C (86°F), can lead to significant increases in mental illness (Obradovich et al. 2018).
People with preexisting mental illness are at increased risk following weather-related events (Trombley et al. 2017), as are youth (Paulson et al. 2015; Orengo-Aguayo et al. 2019). Likewise, climate “surprises” (see Section 2) such as flooding (Lamond et al. 2015), wildfires, or storms have been shown to impact mental health. Those impacts include increases in post-traumatic stress disorder (PTSD), anxiety, depression, substance abuse, and suicidal thoughts. A sense of community loss and, in many cases, displacement can also result following sudden extreme events, or they may occur over time with slower, sustained climate change impacts (e.g., persistent drought or sea-level rise) (Hayes et al. 2018; Palinkas and Wong 2019).
Montana has one of the highest per capita suicide rates in the country (CDC 2018; AAS 2020a,b). This unfortunate reality, coupled with limited access to mental health professionals in most rural areas of the state, greatly heightens the importance of preparedness planning in Montana to address anxiety, stress, and other mental health issues exacerbated by climate change.
Montana has one of the highest per capita suicide rates in the country (CDC 2018; AAS 2020a,b), discussed in detail in Section 4. This unfortunate reality, coupled with limited access to mental health professionals in most rural areas of the state, greatly heightens the importance of preparedness planning in Montana to address anxiety, stress, and other mental health issues exacerbated by climate change (see sidebar). The Montana health workforce does not have widely available access to training on how to address climate anxiety and post-disaster trauma; nor does it have information on the tracking of climate stressors (Doppelt 2016).
 Montanans could feel indirect influences of sea-level rise, for example if coastal populations are forced to relocate inland or coastal grain export terminals important to the Montana economy must be moved.
 Dehydration, or the excessive loss of body water, can have many causes, including heat exposure, kidney disease, and diseases of the gastrointestinal tract that cause vomiting or diarrhea.
 Figure 2-1 provides a map showing and naming Montana’s 56 counties.
 Both heat index and general circulation models are described in Section 2.
 See Appendix A for a complete explanation of socioeconomic variables and their weighting to derive a heat vulnerability index.
 According to the US Environmental Protection Agency (USEPA undated): “Heat islands occur on the surface and in the atmosphere. On a hot, sunny summer day, the sun can heat dry, exposed urban surfaces, such as roofs and pavement, to temperatures 50–90°F (27–50°C) hotter than the air, while shaded or moist surfaces—often in more rural surroundings—remain close to air temperatures. Surface urban heat islands are typically present day and night, but tend to be strongest during the day when the sun is shining.”
 The USEPA developed the AQI scale as a simple way to convey how clean or polluted air is. The AQI scale has six levels: 0-50 good; 51-100 Moderate; 101-150 Unhealthy for sensitive groups; 151-200 Unhealthy; 201-300 Very unhealthy; 301-500 Hazardous.
 The report is based on data collected from 2016-2018. The ten Montana counties are Fergus, Flathead, Gallatin, Lewis and Clark, Lincoln, Missoula, Powder River, Ravalli, Rosebud, and Silver Bow.
 Ecological health may also be impacted, but here we focus on human health.
 Although commonly referred to as blue-green algae, cyanobacteria are a group of photosynthetic bacteria.
 Conversely, in some cases drought can increase the concentration of nutrients (Balla et al. 2011; Gooding et al. 2008).
 A mosquito pool is described by the West Umatilla Mosquito Control District as a collection of mosquitoes (usually about 50) of any given species or group (e.g., Culex spp. mosquitoes) that are likel