Activities that involve very complex and unpredictable problems are still relying on human decision-making and manual tools like paper forms. This is still the case for decision-making within tactical planning in a major incident, where the collective knowledge of multi-expertise specialists is essential to make urgent and effective decisions. Specialists tend to reject tools that jeopardize the decision agility required, as it can put human lives at risk and cause major damages to the environment and property. Communications and management are challenges, as these specialists have each their own expert language. This thesis proposes a planning model that keeps decisions with specialists and allows them to use their own expressions for tactical planning, but incorporates expressions context traceability, authority control over these expressions, and expressions storage for reuse. These features were implemented in a Web tool that aims at empowering decision-making specialists, but tries to preserve the attributes of paper forms. The Web tool was evaluated in oil and gas industry emergency scenarios, and evaluation results indicated that the model s approach enables important improvements in tactical planning communications and management within this context.