Wash the avocados, cut them in half, remove pits, and remove the flesh from the peel. Coarsely chop the avocado flesh and place it into a bowl.
Add lime juice, stir the avocados and lime juice together, coat well, as this will help to prevent browning.
Add in salt, jalapenos, cilantro, garlic powder, and gently mash the avocados breaking the coarsely chopped chunks into smaller pieces. You will want to completely mash about half of the mixture.
Add the red onions and tomatoes. Stir to combine well.
Cover bowl with plastic wrap and refrigerate for at least 30 minutes before serving.