Impacts can be severe when storms bear down on areas with dense populations. But while storms can cause millions of dollars worth of damage to individuals and companies, there are some businesses that walk away with positive impacts. For example, engineering firms, hardware and home improvement companies, and generator manufactures often see revenue increases as a direct result of weather events.

While storms rarely result in long-term financial improvements and companies should not count on them to improve their long-term revenue, a business increase during storm season can be enough to shift investor sentiment and cause a rally in stock values. Below are some stocks that may rally as the result of a weather event.

The Home Depot and Lowe’s

The Home Depot, Inc. (NYSE: HD) and Lowe’s Companies, Inc. (NYSE: LOW) are two companies that may see an increase in business in a weather event's aftermath. These companies are top picks to buy ahead of a storm for the potential increase in stock value, as they can still see an increase in sales even if a weather event does not have a large impact. The Home Depot and Lowe’s sell supplies that people need before a storm, including batteries, snow shovels, generators and various building materials to prepare for the storm. If the storm ends up being significant, sales see another increase in the aftermath as consumers purchase materials needed to clean up and rebuild.

Generac Holdings

Demand for generators increases if a storm results in major power losses. This is a positive for Generac Holdings’ (NYSE: GNRC) business. Generac was the first to engineer affordable home standby generators and is the top manufacturer of home backup generators, as of 2016. It provides portable, residential, commercial and industrial generators that are in high demand if a weather event results in power outages.

Proctor & Gamble

Proctor & Gamble (NYSE:PG) may seem like a dubious pick, as the company is well-known for cleaning and beauty products, but Duracell is one of its major business lines. Battery sales increase before storms as consumers stock up on batteries to power their flashlights and radios.

Engineering Companies

Engineering companies often benefit from rebuilding efforts after major storms. Picks for engineering companies include AECOM (NYSE:ACM) and Fluor Corp. (NYSE:FLR). Both of these companies are major government contractors, which means they can potentially benefit from federal disaster relief. In addition, Fluor has a diverse business including engineering, procurement, construction, fabrication and modularization, commissioning and maintenance, and project management services, all of which may see additional revenue following major storms. AECOM's business is equally diverse, as it provides services for projects including highways, bridges, government and commercial buildings, water facilities, and power transmission and distribution.