Home » Supplemental Figures for the April 2012 La Niña Drought Tracker

Supplemental Figures for the April 2012 La Niña Drought Tracker

Supplemental Figure 1. More than 200 percent of average precipitation fell in most of Arizona and New Mexico in December, providing a significant proportion of the total winter precipitation. Source: High Plains Regional Climate Center

Supplemental Figure 2. March was the third consecutive dry month for most of Arizona and New Mexico, and many regions experienced less than 50 percent of average precipitation. Source: High Plains Regional Climate Center

Supplemental Figure 3. Extreme drought has developed in central Arizona as a result of scant rain since the end of December. In Phoenix, only one storm in the last 90 days, which occurred in mid-March, generated precipitation. Source: NOAA-Climate Prediction Center

Supplemental Figure 4. Crop and pasture lands are dry as a result of scant precipitation. This causes farmers to pump more groundwater and ranchers to haul additional water to desiccating stock ponds. Source: National Drought Mitigation Center

Supplemental Figure 5. Dry weather combined with expected windy weather (typical during the April¬–July period) has elevated the risk of wildland fires in parts of the Southwest. Source: Southwest Coordination Center

Supplemental Figure 6. Below-average snowfall and recent warm temperatures have melted snowpacks in the Upper Colorado River and Rio Grande basins earlier than normal; snowpacks at many monitoring sites are less than the lowest 5 percent in the historical record for this date. Source: Natural Resources Conservation Service  

Supplemental Figure 7. Below-average precipitation in the Upper Colorado River Basin has led to very low spring streamflow projections. There is a 50 percent chance that the total April–July inflow to Lake Powell will be below 44 percent of average, which amounts to about 4.5 million acre-feet less than average, according to the April 1 forecast. Source: Natural Resources Conservation Service

Supplemental Figure 8. The April–June period is historically the driest season for most of the Southwest. Less than 12 percent of the total annual precipitation falls in this period for most of Arizona and southwestern New Mexico. The percentages were calculated using data from 1961–1990. Source: Western Regional Climate Center

Supplemental Figure 9. The seasonal temperature outlook, which is partly based on recent warming trends, calls for increased chances for warmer-than-average conditions for the April–June period. Source: NOAA-Climate Prediction Center

Supplemental Figure 10. The April precipitation forecast calls for increased chances for below-average rainfall in all of Arizona and New Mexico. In recent decades, spring precipitation has been declining. Source NOAA-Climate Prediction Center

Supplemental Figure 11. Between 60 and 80 percent of the La Niña events during the 1950–2008 period contributed to precipitation totals between 0.4 (10 mm) and 1.2 inches (30 mm) below the April–June average in many parts of Arizona and New Mexico. The image on the right displays the percent of La Niña events in which the anomalies in the left image occurred. The year of the La Niña events are indicated at the bottom of the figure. Source: NOAA-Climate Prediction Center

Supplemental Figure 12. The Seasonal Drought Outlook calls for drought to persist, intensify, or develop in all of Arizona and New Mexico during the April–June period. This period is historically dry and therefore offers few opportunities for widespread and heavy rain and snow needed to improve drought conditions. Source: NOAA-Climate Prediction Center

Supplemental Figure 13. Above-average temperatures in the past 30 days have melted snowpacks across the Southwest and Rocky Mountains. Temperatures have been particularly warm in the Upper Colorado River and Rio Grande basins. Source: High Plains Regional Climate Center

Supplemental Figure 14. Low snowpacks and the expectation for minimal precipitation in coming months (due to the historically dry conditions for many parts of Arizona and New Mexico) feed the below-average spring streamflow forecast in the Southwest. The forecast, issued on April 1, calls for the Little Colorado, Verde, Salt, and Gila rivers to be 30, 41, 28, and 7 percent of average, respectively. These numbers are lower than one month ago. Source: Natural Resources Conservation Service